gce january 2004 report on the examination - … 12,13/a level physics past papers... · report on...

GCE 2004

January Series

Report on the Examination

Advanced Subsidiary – 5451Advanced - 6451

GCE PhysicsSpecification A

� Advanced Subsidiary

� Advanced

Further copies of this Report on the Examination are available from:

Publications Department, Aldon House, 39, Heald Grove, Rusholme, Manchester, M14 4NA

Tel: 0161 953 1170

or

download from the AQA website: www.aqa.org.uk

© Assessment and Qualifications Alliance 2004

COPYRIGHTAQA retains the copyright on all its publications. However, registered centres for AQA are permitted to copymaterial from this booklet for their own internal use, with the following important exception: AQA cannot givepermission to centres to photocopy any material that is acknowledged to a third party even for internal usewithin the centre.

Set and published by the Assessment and Qualifications Alliance.

The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee, registered in England and Wales 3644723 and a

registered charity number 1073334. Registered address AQA, Devas Street, Manchester M15 6EX. Dr Michael Cresswell Director General.

CONTENTS

AS Units

Page No.

PA01......................................................................................................4

PA02......................................................................................................6

PHA3/P .................................................................................................8

PHA3/C.............................................................................................. 12

PHA3/W ............................................................................................ 14

A2 Units

Page No.

PAO4 Section A .............................................................................. 16

PA04 Section B............................................................................... 19

PHAP Units 5-9 Practical ............................................................ 21

PHAC Units 5-9 Coursework...................................................... 25

PHA5/W – PHA9/W Section A................................................... 25

PHA5/W ............................................................................................ 26

PHA6/W ............................................................................................ 28

PHA7/W ............................................................................................ 30

PHA8/W ............................................................................................ 31

PHA9/W ............................................................................................ 32

PA10................................................................................................... 34

Mark Ranges and Award of Grades ...................................................................... 37

Physics A - Advanced Report on the Examination

��4

Physics

Specification A

Advanced Subsidiary Examination

The January 2004 examination saw a significant increase in the number of candidates enteredfor the PA01 and PA02 examinations compared with the January 2003 entry. Unit 1population increased by almost 22% and unit 2 by 24%. This increased number ofcandidates, some of whom may have transferred forward from previous June entries, may bea consequence of the changes made to the lengths of the papers and the consecutive schedulefor AS. Such a large increase could significantly affect the ability profile of the Januarycohort. The entry for the third written paper, PHA3/W, stayed reasonably the same.

The examiners were well pleased with the response to all the examinations and there was no

evidence to suggest that any particular topic in the Specification had not been taught. With

such large entries, examiners expected a certain amount of unit errors to be incurred.

Similarly with significant figure errors. The Quality of Written Communication appears to

have improved over the years. Candidates do seem to be aware that the maximum marks

available for QWC constitute 4% of the total marks for the paper and consequently take

greater care when answering the sections designated for QWC.

Unit 1: PA01: Particles, Radiation and Quantum Phenomena

General Comments

The paper was well received by the candidates and only the weakest failed to attempt allquestions. All marking points were awarded and some scripts scored full marks. The paperenabled weaker candidates to make some attempt at most questions and allowed the moreable to gain 80% or more of the marks. It thus discriminated well and at the same time gavecandidates a positive feeling of success and ability to answer questions.

Question 1

A minority of candidates failed to score the two marks in part (a) because they interpretednucleons as neutrons. Part (b) presented more of a challenge for the more able candidatebecause the fractional charge and the fractional baryon number for quarks were concepts thatwere not universally understood. Many candidates took this part of the question to mean,‘Are the quantities conserved or not?’ The other common error was failing to assign correctlepton numbers. Because of these difficulties the question turned out to be a gooddiscriminator between candidates.

Report on the Examination Advanced - Physics A

�� 5

In part (c) the majority of candidates were aware that the positron and the electron suffered

annihilation but only the better candidates referred to the production of two � photons. A

noticeable number of the less able candidates confused annihilation with pair production.

Question 2

The average candidate performed well on this question. Many candidates lost marks by

describing the meson as having two quarks rather than having a quark plus an antiquark.

Other candidates lost marks because of the ambiguous way in which antiquarks were

included in their description of a baryon.

In part (b) many of the weaker candidates were under the illusion that a lepton had a quarkstructure and also that the change to the quark structure during the decay was a change to anantiquark rather than a down quark changing to an up quark.

Question 3

As in previous years only a minority of candidates completed the ray diagram correctly, thus

gaining full marks. The first error in part (a) occurred at the point where the ray entered the

fibre; many candidates drew the refracted ray along the normal. There was a general lack of

care in not making the angle of incidence different in value to the angle of reflection.

Additionally, many candidates did not show any refraction at the far end of the fibre. Some

of the TIR angles along the fibre were very carelessly drawn and the allocated mark was

withheld on several occasions. Although most candidates were aware of the change in the

speed of light as the ray entered the fibre, many failed to state that there was also a change in

speed as the ray left the fibre.

The calculation in part (b) (i) was usually carried out correctly, but in part (ii) the less able

candidates did not attempt to use both refractive indices. Many of the statements made in

answer to part (iii) were of a very general nature and did not explicitly refer to surface

scratches or contamination.

Question 4

Part (a) caused problems for a significant number of candidates. It was common to find the

frequency of the incident radiation being calculated and then the value substituted back into

the photoelectric equation in order to calculate the energy. The unit of work function was

often incorrect, resulting in a lost mark.

Part (b) discriminated very well, even in the top ability range. For those candidates who

failed on this part, some of the more common errors were: taking the energy to be

proportional to the wavelength, doubling the value of the work function instead of doubling

the incident energy of each photon and basing the energy of the photon on the photoelectron

energy.


��6

Question 5

The explanation of the excitation process in part (a)(i) was done well. There were very few

references to ionisation, which has occurred in previous papers, and also practically no

candidates referred to an electron leaving a metal. There was a tendency to continue the

explanation into the relaxation process, which was unnecessary. In part (ii) several

candidates worked backwards to the expected answer. These candidates typically wrote that

the wavelength was fixed because the frequency was fixed because the energy was fixed. It

was easy for these candidates to miss the relevant marking points. Very few candidates gave

clear statements about the energy levels occurring at discrete energies or that an electron

drops down an energy level when a photon was emitted.

Part (b) again proved to be a good discriminator. In part (i) several candidates attempted to

use the de Broglie relationship instead of the usual � = ch/E. In parts (ii) and (iii) only about

half the candidates gave the correct transition and the correct direction. Most of them

successfully converted the energy of the transition from joules into eV.

Question 6

Too much time was spent by candidates repeating the wording of the question and explaining

the wave particle duality. There was also a tendency to concentrate on one or two pieces of

evidence, thereby excluding themselves from gaining full marks because of the lack of

coverage. It was this aspect of the submitted answers that really governed the marks awarded,

rather than candidates making errors. It was also clear that many candidates thought it only

necessary to discuss the wave view of an electron and the particle view of an electromagnetic

wave.

Unit 2: PA02: Mechanics and Molecular Theory

General Comments

The performance of candidates in this unit was generally good with none of the questionsproving inaccessible. The structure of the questions helped to improve accessibility for theweaker candidates. Overall the candidates performed better than in January 2003 and severalwere awarded full marks. It was also felt by the examiners that this year’s questions, with alower total, lacked some of the more difficult sections seen in earlier papers. Candidatesfound questions 2 and 3 the most difficult and this was true for all ability levels. Presentationwas generally satisfactory and candidates set out their calculations so that there was a logicalstructure to the answers. Significant figure errors were common in question 3 and unit errorscommon in question 2. The Quality of Written Communication was good and it was notunusual to find weak candidates being awarded full marks for this skill.

Question 1

This question was done well with most candidates in part (a) successfully explaining the

meaning of a scalar quantity and able to give suitable examples. Calculating the third force

and the angle in part (b) did not present too many problems and candidates across the ability

range approached this task with confidence. A few candidates did opt for a scale drawing but

they were very much in the minority.


�� 7

Question 2

The question, as a whole, proved to be a good discriminator. The various calculations in part

(a) were quite demanding for a significant proportion of the candidates and unit errors were

quite common for all the quantities involved, including those for the more straightforward

quantities such as acceleration and speed.

Candidates were asked to sketch two graphs in part (b). This proved to be quite a difficult

exercise with the non-linear, distance vs. time, graph being the most difficult to draw

correctly.

Part (c) produced the same problems that questions of this type have produced in previous

papers. Many candidates insisted on using Newton’s third law incorrectly and consequently

getting into real trouble. Statements such as “the air resistance is the reaction to the driving

force action” were common and were awarded zero marks.

Question 3

Again candidates found this a demanding question and a significant minority were not even

able to convert the temperature from Celsius to Kelvin in part (a). In the same section, the

calculation of number of moles of gas and the number of gas molecules also proved difficult

and significant figure errors were common.

Part (b) realised better answers, although many candidates did not seem to appreciate that

temperature is related to the mean kinetic energy and not to the kinetic energy of an

individual molecule.

Question 4

This question, based on the principle of moments, differed from previous questions on this

topic, in that a descriptive question on moments had not been previously set. Candidates

generally rose to the challenge and approached the description of the experiment in parts (b)

and (c) with confidence. The procedural descriptions did tend to lack clarity but candidates

were generally able to score reasonable marks. A minority of candidates totally

misunderstood the question and described experiments which verified the conservation of

momentum.

Question 5

The last question in the paper was generally done well and candidates across the ability range

were able to perform the various calculations successfully. A minority were confused by the

need to use only 60% of the kinetic energy, but because marks were awarded for

consequential errors, this did not prove to be too much of a penalty.


��8

Unit 3: PHA3/P: Practical

General Comments

Although the entry for January 2004 had increased by about 10% over the January 2003

entry, the statistical distribution of marks for the two examinations was strikingly similar.

Candidates seemed to find question 1 slightly easier and question 2 slightly harder than

previously, but the two effects cancelled to produce the same mean mark.

Within both questions all assessment objectives discriminated well, with every mark in the

range for AO3a (Planning) and for AO3d (Evaluating) being utilised in the distribution.

Candidates who demonstrated A-grade ability could generally expect to gain 7 or 8 marks

(out of 8) for AO3a and at least 6 (out of 8) for each of AO3b (Implementing) and AO3c

(Analysing). Although they generally did better in AO3d than other candidates, there was

more variation in their scores and it was this assessment objective that provided the best

discrimination among this group.

Candidates who might be expected to achieve a grade B or C scored comparatively well in

AO3b and AO3c although slightly below the level achieved by the stronger candidates. They

usually achieved at least half marks in AO3a but often less than half marks in AO3d. It was

their weaker performance in these assessment objectives that provided the most marked

distinction between the work of this grade of ability and that of the best candidates.

Candidates who appeared to be of grade D standard and below performed less well in all

assessment objectives but particularly so in AO3a and AO3d, where many gained no mark in

either or both objectives.

The presentation of scripts was generally good and often included detailed sketches thatclarified issues that were left unresolved in the written part of the answer, but the tabulationof data was an area where the presentation of work could vary considerably. Graphical workwas frequently undermined by the obsessive need to include an origin or by the use of scalesthat made interpretation difficult.

Although most candidates found the questions quite accessible, it is puzzling how often the

attempts at question 2 seemed laboured, with careless or inaccurate work from the outset. In

this question most candidates chose to determine �y without making full use of the masses

supplied and the majority were reluctant to utilise more than half the length of the suspended

ruler for their values of x.

Of the relatively few candidates who provided a satisfactory graph only a very small number

were able to combine the gradient result with that of the initial measurements to obtain an

answer for which full credit could be given. There was widespread reluctance to give the

answer to the evaluation of G

y� to more that 2 significant figures and suitable units were

hardly ever provided.


�� 9

Answers to question 1 tended to be over-long and often contained repetitive, generalised

comments that could attract little or no credit. Simple, concise answers were sufficient in

many instances for full credit to be given, with many candidates showing a clear

understanding of the physical principles of the situation. The time may be approaching when

candidates will have to be restricted, for their own good, in the amount they can be allowed to

write.

Candidates appeared to have ample time to complete the examination.

Question 1

Candidates were required to describe a method of investigating whether a quantitative link

existed between the diameter of a hydraulic jump, produced as water falls on to a horizontal

plate, and the flow rate of the water incident on the plate.

The question proved very accessible to the candidates, most of whom showed a reasonable

understanding of the problem. Very few failed to identify that the volume of water collected

in a fixed time (or the time taken to collect a fixed volume) would enable the flow rate to be

determined. However, a few candidates suggested impractical ideas where the speed, height

and cross sectional area of the water stream would be determined.

Most candidates specified a suitable method of finding the diameter of the jump (those who

said they would measure the radius were not penalised) and a large number appreciated the

need to measure the diameter of the jump without interfering with the flow. Suggestions as

to how this would be done included the use of transparent plates with rulers below or the use

of callipers and dividers to pinpoint the diameter. Use of a stopclock was almost universally

given credit, except where this was used to find the transit time of the water between the tap

and the plate.

The majority of candidates stated that in order to determine the flow rate they would measure

the volume of water (using a measuring cylinder) for a certain time. The use of standard

containers to collect a fixed volume of water was also allowed, providing some idea was

conveyed as to how the volume of the water contained was known. Some suggestions for

finding the flow rate were impractical, with impossibly small volumes or short intervals of

time to collect it being suggested. A few candidates proposed calibrating the tap and

introducing some rotary scale against which the position of the tap could be judged. Others

proposed some type of ‘flow meter linked to a computer’, a proposal that was given no credit.

A number of candidates suggested that the time taken for a graduated container (such as a

burette) to empty should be found; full credit could not be given in such cases since the

candidate had failed to appreciate that this could not provide a uniform flow rate. Others

proposed to carry out the investigation with water falling into a tray or container from which

water could not naturally drain. Once again, full credit was not given, as the ensuing

flooding of the plate would affect the size of the jump formed.

Most candidates clearly showed that they intended to vary the flow rate and measure further

jump diameters, and provided that the procedure they had outlined to find the flow rate would

work, credit was given. Many went on to suggest that a graph should be drawn, but for credit

to be given, some attempt had to be made to explain how this could reveal whether a

quantitative relationship between jump diameter and flow rate existed.


��10

The bulk of marks awarded were for describing how the measurements were made (4 marks)

and for devising a suitable strategy to satisfy the set objective (3 marks) but some candidates

also gained credit for identifying that the distance between the tap and the plate should be

maintained constant.

Marks for suggesting suitable procedures and identifying the difficulty that these overcame

were hard to earn. As is often the case, many candidates provided a procedure but failed to

give the associated difficulty and bland statements about ‘repeating and averaging readings to

reduce uncertainty’ could seldom earn credit.

Some of the better procedures seen were repeating the diameter measurement in different

directions, thereby compensating the possibility that the jump was not perfectly circular; to

wait for the shape of the jump to stabilise before taking measurements and to collect the

water over a long period or collect a large volume to reduce uncertainty in the flow rate.

Question 2

Candidates were required to investigate the equilibrium of a loaded metre ruler suspended

from a horizontal beam, by a combination of a wire of variable length and four

interconnected springs.

Candidates found this to be a more accessible problem than that set in January 2003, with

straightforward processing of the data and opportunities from the outset to limit the impact of

experimental errors on the evaluation of y

G

�. Judging from the distribution of points on the

graphs seen, the majority of candidates carried out the experiment without difficulty and the

answers given in part (e) (AO3d) confirmed that most were capable of arranging the

suspended beam as required and measuring y reliably.

Where careful measurements were made in part (a), it was possible to check that the values of

�y were reliable but some candidates chose not to determine the value in a way that allowed

them to check for random error. Full credit was given less often than expected, mainly

because candidates had failed to measure 2�y or 3�y in order to obtain their answer. Others

lost marks because they failed to give the reading to the nearest millimetre, as expected.

In part (b) both marks were generally awarded for tabulation, but it was common to withhold

one mark for the results because candidates seldom made sufficient use of the scope available

for measurements of x. Candidates were required to utilise at least 50 cm of the available

range, but a surprising number used considerably less distance. Consistent use of significant

figures was generally widespread and most earned the relevant mark. The straightforward

nature of the exercise dictated that for the quality mark to be awarded, all five points should

fall within 2 mm on a suitably scaled graph; this often provided a useful discriminator in

favour of those who had used a wide range of x values.

Graphical work continues to be undermined by poor or inappropriate scaling. The inclusion

of the origin compresses the vertical scale, but there were significant numbers who chose

inconvenient scales simply to extend the distribution of points: this should be discouraged as

it makes plotting difficult and the determination of the gradient unreliable.

Axes were usually well marked but there were some instances of wrongly or inappropriately

marked points.


�� 11

Gradient calculations were usually made with sufficiently large y and x steps, except where

compressed graph scales had made the line too shallow. It was a major disappointment to

find how few candidates gained credit for their answers to the evaluation of y

G

�. In some

cases the fault lay with the value determined for �y in part (a), but in general the loss of

marks was due to the lack of a unit and/or the contraction of the result to 2 significant figures.

Even the better candidates lost up to three of the six marks available in part (e) (AO3d), while

the weakest candidates generally scored only one or two marks. In part (e)(i) the required

answer was that the value of y was checked at each end of the apparatus; the suspended ruler

could be presumed to be horizontal when these two readings matched. Many candidates

stated precisely this. Others chose to measure up from the floor (or from the bench) to each

end of the suspended ruler and check that these readings matched, but in such cases they had

to state that the ruler used to make the measurement was vertical. Any explanation which

involved a setsquare to compare the suspended ruler with the suspension wires was not given

credit.

The majority of candidates understood that the vertical intercept on the graph would give the

value of y if the 300 g mass was removed from the suspended ruler, but few explained that

this was so because when placed directly below the wire (i.e. x = 0), the mass would exert no

turning moment and so be effectively removed.

Most candidates correctly deduced that if the experiment was repeated using a 200 g mass,

the gradient of the graph would be reduced. However, most argued that this would be due to

larger x values, which may be true, but is also ambiguous (larger x values can only lead to a

reduced gradient if the values are proportionally larger as opposed to being incrementally

larger). If candidates explained that x values would be increased to produce the same turning

moment (given the reduction in the force applied to the beam) then full credit was given.


��12

Unit 3: PHA3/C: Coursework

A significant proportion of the candidates entered for this module were carrying forward

marks from the Summer 2003 examination. The comments in this report are therefore based

on new work submitted from a relatively small number of centres.

Most Centres completed the administration procedures correctly and copies of Centre

Marksheets and samples of candidates work reached moderators by the prescribed deadline.

In a few cases however, there was some confusion as to which copies of the Centre

Marksheet should be sent to the moderator. In small centres of less than 20 candidates, just

the pink copy should be sent, together with the candidates work and the yellow copy retained

by the Centre. For larger Centres, both pink and yellow copies of the Centre Marksheet

should be sent to the moderator. The yellow copy will be returned, specifying the samples to

be sent to the moderator.

Overall, the quality of annotation was good, with only a few Centres failing to adequately

annotate the work submitted. It should be noted that every marking point must be annotated

at the precise point where the mark was awarded. The annotation should be written in the

format ‘A4b’, ‘B6a’ etc. referring to the appropriate marking point. Written comments are

also helpful, particularly in clarifying why a particular ‘marginal’ point has been awarded.

The use of a suitable marking grid to record the individual marking points is also strongly

recommended. This makes it much easier to interpret the hierarchical scheme and determine

the total mark for each skill.

As in previous years a significant number of adjustments were made to marks submitted by

centres. Almost all Centres applied the hierarchical scheme correctly. Mark adjustments were

mainly due to misinterpretation of specific points in the assessment criteria; these are

explained in more detail below. Due to the hierarchical nature of the scheme however, one

error in interpretation of the criteria can cause a significant adjustment to the overall mark,

e.g. a candidate who, in the opinion of the moderator, has failed to achieve A4c (fully

labelled diagram), will be limited to a maximum mark of 3 for planning. If this mark had

been awarded by the centre this might result in a mark change from 8 to 3.

In most cases the investigations used were appropriate, allowing their candidates access to the

full range of assessment criteria. Experiments on measurement of resistivity and emf/internal

resistance were again very popular and successful in allowing a full range of marks to be

achieved by candidates. A small number of centres presented investigations which did not

allow their candidates access to all the marking criteria. This was usually because the

experiment did not generate a suitable graph from which gradients and intercepts could be

calculated, e.g. investigations involving solar cells.

As in previous examinations a small proportion of candidates made use of ICT. Whilst

appropriate use of ICT is to be encouraged as part of investigative science, many candidates

were penalised due to graphs and results tables which did not meet the assessment criteria.

Graphs drawn by ICT software must meet exactly the same criteria as hand drawn graphs.

They should produce a graph, which covers a full side of A4 paper with a suitable title and

fully labelled axes. Points should be plotted as points or crosses and not shapes, such as large

squares or diamonds, which make precise location of the plotted point more difficult. The

line of best fit should be drawn taking account of any anomalous points. The graph should


�� 13

have suitable gridlines so that accurate readings for gradients or intercepts can be recorded. A

suitably large triangle for measurement of gradient must also be shown.

The advice which follows addresses issues raised by moderators on the marking of specific

skills. Many of these points were also discussed in the recent series of Teacher’s Support

Meetings held last autumn.

In skill A there were still a few cases of candidates failing to mention a consideration of

safety issues, thereby effectively limiting their mark to a maximum of 1. To achieve A4c,

diagrams must be two dimensional, fully labelled and dimensions being measured must be

clearly indicated. If the length of a string or wire is being measured it should be drawn as a

straight line with the dimension indicated. A4c was the most common point misinterpreted by

centres, and frequently caused a significant adjustment in the marks awarded. To achieve

A6d full instrument specification is required and for electric meters this requires both range

and sensitivity. Occasionally unrealistic instrument sensitivities were quoted, e.g. metre rules

reading to �0.05 mm.

In skill B, some candidates failed to take enough readings with appropriate repeats to achieve

B4c. In an experiment to investigate the variation of resistance with the length of wire, it

would be expected that candidates do at least 7 or more different lengths with repeat readings

for resistance at each length. Some centres awarded this mark incorrectly where candidates

had only done 5 or 6 different readings.

Quoting results to an inappropriate number of significant figures was the main cause for

concern in skill B. This usually occurred where a length measured to the nearest mm was

quoted only to the nearest cm, e.g. 0.20 m rather than 0.200 m, and often results in a mark

adjustment from 8 to 5 on this skill.

In B6d, candidates must clearly identify the significant source(s) of error which occurred in

their experiment. Although in the planning stage they might have suggested a particular error,

a further statement would be required after results have been taken to confirm whether or not

this is still considered to be the most significant error.

In skill C, to achieve C4c an appropriate scale must be used so that the plotted points occupy

more than half the length of each axis. If this makes it impossible to read a particular

intercept directly, a suitable calculation should be done instead. Some centres awarded C4c

for graphs with no titles and where the plotted points occupied less than a quarter of the area

of the paper. This caused significant adjustment to the marks awarded, effectively limiting

the mark for skill C to a maximum of 3.

In skill D the majority of candidates scored less than in the other skill areas. Many candidates

failed to achieve all four marking points in D2, effectively limiting their mark to a maximum

of 1 for this skill. In particular, for D2b a simple statement about discrepancies or anomalous

results is required. For D2c, candidates must state whether there is much variation in their

repeated results, indicating the level of uncertainty in the data. In D4b, candidates frequently

calculated errors based on instrument sensitivity only. Where possible the error estimate

should be based on the spread of repeated results, e.g. in an experiment to investigate the

variation of resistance with length of wire, the error in length might reasonably be based on

the accuracy of the rule (�1mm). The error in resistance, however, should be taken from the


��14

spread of repeated readings, and not the sensitivity of the meters used. In D6a a large

proportion of candidates are unsure of the difference between random and systematic errors.

Unit 3: PHA3/W: Current Electricity and Elastic Properties of Solids

General Comments

All questions on the paper worked satisfactorily and no particular question proved to be too

difficult for the candidates. All marking points were awarded and maximum marks were

gained by a few candidates. Very few incorrect units were presented, but the unit of

resistivity in question 2 did create some difficulty. Significant figure errors were few and far

between and seemed to occur at random throughout the paper. It was pleasing to note that

very few answers were presented in the form of fractions. The Quality of Written

Communication was of a good standard. It does seem that extra care is taken when

candidates know which sections are being scrutinised. Unfortunately, this attention to quality

in certain sections did not manifest itself throughout the whole paper.

Question 1

The question involved straightforward calculations on voltage, resistance and current. In part

(a)(i) it was hoped that candidates would have spotted the correct voltage across each lamp

by inspection. Surprisingly, even those who managed to get the wrong answer in part (i)

nevertheless ignored their answer and proceeded from first principles to obtain the correct

answer to part (ii).

Part (b) involved the same circuit components as in part (a) but connected differently. The

majority of candidates showed that the current from the battery was the value given in the

question. Using this value they then proceeded to argue or calculate the current in each lamp.

Those candidates who merely halved the current value obtained in part (i) without any

reasoning did not gain the mark.

Although the question told the candidates that the current through each lamp was the same in

both circuits it was disappointing to find in part (c) how many candidates tried to argue that

the brightness of the bulbs in the 2nd circuit would be different to that in the first, the main

thrust of their argument being that the voltage across each bulb was different and therefore

that the brightness would be different.

Question 2

The large majority of candidates gained the two available marks in part (a) without much

difficulty and supported their choice of conductor with the correct argument.

Some care was required in part (b) in reading the graph accurately and the fact that the

majority of candidates simply put down 0.7 A at a voltage of 1.0 V, showed that they gave the

graph no more than a cursory glance. It should also be pointed out that drawing vertical and

horizontal lines in thick pencil or in ink on the graph very often obliterates the required point

and accurate values can then not be read. The explanation in part (b)(ii) of why the resistance

increased was satisfactorily done in terms of the increased temperature of the filament,

although for a complete answer it should be pointed out that it is the current that heats up the

filament. Very often there was no direct reference to the temperature of the filament, but


�� 15

instead a general phrase such as “...leads to an increase in temperature...” or “ heat is

created...”.

The calculation on resistivity in part (c) was more often than not carried out successfully.

The errors which did occur was taking the resistance as the gradient, and not as the inverse of

the gradient and omitting or using wrong units.

Some circuit diagrams in part (d) were very well drawn and the majority of candidates

obtained full marks. The usual omission was a variable resistor or variable supply to alter the

voltage. If a potentiometer is used then it is important to show the ammeter in series with the

filament and not in series with the power supply. Some candidates lost a mark by connecting

the voltage and current sensor directly to a computer rather than through the data logger.

Question 3

High marks were usually obtained in this question. Very few candidates failed to gain full

marks in part (a) although it was sad to see some giving the peak voltage as Vrms/�2.

In part (b) a large number of candidates were obviously familiar with the correct terminology

of the oscilloscope controls, but other terms were also accepted. The calculations of the new

settings were generally well performed.

Question 4

Candidates found this question very accessible and many gained full marks. In part (a) the

meaning of emf seems to be reasonably well understood with most candidates opting for the

voltage when no current passed through the circuit. Others defined it correctly in terms of

energy per unit coulomb. There were, unfortunately, many candidates who, apparently, had

not encountered the definition of emf and merely quoted electromagnetic force, or even tried

to define it in terms of a force in the circuit. The calculation of the current in part (ii) was

well done and in part (iii) correct substitution of values into the equation � = V + Ir gave r =

0.80 �.

Part (b) was involved with calculation of power and energy and although the majority of

candidates obtained the correct answer for the power dissipated in the 2.4 � resistor, fewer

had the correct answer for the total power dissipated in the circuit and a disappointing

number had the correct value for the energy wasted the battery. The usual answer to the last

part was to give the energy in the complete circuit. Whether this was due to inaccurate

reading of the question or due to lack of understanding could not be decided.

Question 5

In part (a) the definitions of tensile stress and tensile strain were usually correct although

some candidates were penalised for not stating that the area involved was the cross-sectional

area. A definition of tensile stress as force per unit area was not accepted.

Part (b) gave candidates the opportunity to write at length on what they knew about stress-

strain curves. Most accounts started off well with the easily recognisable linear region

obeying Hooke’s law. A linear region given in terms of a constant Young modulus was not

accepted. The point A on the graph was not always defined as the limit of proportionality.

After this initial section the descriptions became more vague. There seems to be some


��16

confusion as to where the elastic limit occurs and this is not helped by some textbooks. In

this question the examiners were prepared to accept that the elastic limit occurred from A to

the region B. A phrase which occurred regularly was ‘plastic deformation’ without any

attempt being made at explaining what it meant. It would have been worthwhile for the

candidates to extend their sentence by stating that the wire did not regain its original length or

shape once the applied force was removed. Many candidates thought that because the graph

became reasonably straight around section C that Hooke’s law was obeyed again. The

impression gained by the examiners was that the topic was, on the whole, loosely taught and

that candidates memorised terms such as elastic limit without fully realising what happened

to the wire.

Question 6

This is the first time since this Specification was introduced that a question on density has

been set. The examiners were pleased to find that the majority of candidates seemed to

understand the topic very well and gained full marks. Unfortunately, candidates who gave

density as � = mass � volume were, because of the nature of the question, penalised quite

heavily, but they could however earn marks for calculating the volume in part (b)(i) and

adding the masses together in part (ii).

Advanced Examination

With the exception of paper PA04, the entry for A2 remained small and thus it is difficult to

generalise on the standard achieved in the option papers and synoptic papers. The entry for

PA04 remained at approximately 3000 (January examinations) and the entry for the synoptic

paper, which is by now becoming well established, almost doubled from January 2003 to 80

candidates this year.

All the Principal examiners were satisfied that the papers had been fair and all questions

accessible to the candidates.

Unit 4: PA04: Section A: Objective Test Questions

The keys to the objective test questions were:

1-C; 2-A; 3-D; 4-D; 5-B; 6-A; 7-C; 8-D; 9-C; 10-C; 11-A; 12-C; 13-C; 14-B; 15-B.

General Comments

The facility of a question is a measure of all candidates attempting a question who choose the

correct option. The mean facility of this paper was 70%, compared to 57% and 60%

respectively in January and June 2003. The facility for individual questions ranged from

90% for question 14 to 52% for question 4.


�� 17

The point biserial index of a question is a measure of how well the question discriminates

between the most able and the least able candidates. The mean point biserial for this paper

was 0.45, slightly higher than the values of 0.41 and 0.44 respectively in January and June

2003.

No fewer than ten of the questions (all except Questions 3, 4, 9, 12 and 15) proved to be easy,

with facilities over 65%, whilst no question was found to be difficult. Only one of the

questions had appeared in an earlier Advanced level examination and in January 2004 the

candidates’ performance on this question was a noticeable improvement over that on the

previous occasion. This contrasts with recent experience with re-banked questions in

previous PA04 papers, where present-day candidates have generally not been able to match

the performances of their predecessors.

Statistical analysis of the results has shown this test to be rather more accessible than the

2003 papers, but also provided some evidence that the cohort taking the paper was slightly

more able. Examiners marking Unit 4 Section B detected a similar trend in the candidates’

abilities.

Question 1 amounted to a two-stage calculation on simple harmonic motion. The facility of

84% was a significant advance on that of 67% in the pre-examination test.

Wrong responses were almost equally divided between distractors A, B and D.

Question 2 was set in the context of a simple pendulum experiment, requiring candidates to

show knowledge of how g could be found from the gradient of a graph of T2 against l. The

facility was 69%, a similar improvement over the pre-test to Question 1. Distractor B, chosen

by one in six, was the most popular incorrect response; this may suggest that these candidates

had difficulty with algebraic re-arrangement.

Question 3 tested the graphical relationship between kinetic energy and displacement in

simple harmonic motion. The facility of 59% was an improvement over the 50% achieved

when this question was pre-tested. Almost one in five of the candidates chose distractor A,

forgetting that there are two cycles of energy for every cycle of displacement

Candidates found Question 4, with a facility of 52%, to be the most demanding question on

this paper, but it was one of the best discriminators. Many candidates have obvious difficulty

in appreciating the function of the defining slit in Young’s experiment, because distractor A

was chosen by almost 20%. Distractor B was nearly as popular, perhaps because problems

with logic made it difficult to interpret what was meant by two ‘decreases’.

Question 5 was not considered easy when it was set, because it involved rather more than a

straightforward answer achieved by direct substitution in n� = d sin�. Only 50% got the

correct answer when this question was pre-tested, but this improved to 67% in the

examination. No doubt the 17% who chose distractor C did so because they forgot to

subtract the angle with n = 2 from the angle with n = 3.

The geo-synchronous satellite in Question 6 did not seriously trouble many of the candidates,

since the facility was 80%. Wrong responses were almost evenly split between the remaining

three distractors, with none attracting more than 8% of the candidates.


��18

Question 7 was also found to be easy (facility 84%), although a lower discrimination index

than the first six questions points to the fact that even the best candidates do not always fully

understand what is happening in circular motion.

Question 8, also on circular motion, involved a calculation. Candidates were rather less

successful with this question and the facility was 65%. However, the same question had been

used in the 1995 A level examination, when the facility was only 59%. Almost a quarter of

the 2004 candidates chose distractor C.

The gravitational field strength at the surface of a planet and its relation with radius and mass

was the subject tested by Question 9. 61% of the candidates selected the correct response, a

10% improvement over the pre-test facility. Distractor B, the most common wrong response,

was chosen by just over one in five of the candidates.

Question 10, with a facility of 66%, examined the variations of electric field strength and

electric potential with distance in a radial field. Distractor D was hardly ever chosen, with

wrong answers divided mainly between distractors A and B.

An unfortunate printing error, for which AQA apologises, meant that an erratum notice had to

be issued for Question 11. This corrected the charge on Q from +6�C to �6�C. In the main,

the candidates showed a good understanding of electric potential, causing the question to

have a facility of 75%. With a 40:60 division of the 100 mm separation, it is not surprising

that the most common wrong response was distractor D (60 mm) when the correct one was A

(40 mm). Question 11 was the weakest discriminator on this paper.

Question 12. Trajectories of charged particles as they pass through electric and magnetic

fields ought to be a fairly simple topic, but the facility of this question improved only slightly,

from 55% to 57%, between pre-test and examination. Candidates who did not understand

these topics were attracted in almost equal numbers to distractors B and D.

Questions 13 and 14, with facilities of 86% and 90% respectively, were the easiest questions

contained in this test. Each question had a pre-test facility of 66%; the dramatic improvement

in facility seems to indicate that candidates are able to revise their work on nuclear

applications much more readily than most of the other topics in Unit 4. Question 14 was not

a particularly good discriminator.

Question 15 had a slightly unusual slant on the familiar topic of controlling a nuclear reactor,

where the effect of the control rods on the average kinetic energy of the neutrons had to be

considered. With a facility of 57% (up from 41% in the pre-test), the question proved to be

satisfactory and gave reasonable discrimination. Around one fifth of the candidates chose

distractor A, and a further one fifth chose C.


�� 19

Unit 4: PA04: Section B : Waves, Fields and Nuclear Energy

General Comments

This section of the Unit 4 examination gave candidates excellent opportunities to show what

they had learned. The examiners considered that it had been the most successful of all the

five papers set on Unit 4 since the introduction of Curriculum 2000. Fewer candidates scored

low total marks, while a greater proportion scored marks of 20 and above than in the previous

January Section B papers. Perhaps this is because centres are becoming more discriminating

about the candidates they enter in January.

Some centres clearly have a policy of entering all their A2 Physics candidates for the Unit 4

examination in January, despite the pressure this places on them to complete the necessary

preparations in four months of teaching. In these circumstances the January test seems to be

regarded by some candidates as a “mock” examination, before the “real” test when they re-sit

Unit 4 in June. Many of these candidates are poorly prepared and consequently obtain low

marks. On the other hand, some centres have a selected group of able students who can cope

admirably with the January examination.

Penalties for transgressions over significant figures often had to be imposed in Question

2(b)(i), where candidates strangely chose to write down answers that included five or six

figures. Units were sometimes omitted from candidates’ answers to Question 4 (b), causing

the loss of the one mark for this part.

Examiners were pleased to see that many candidates made a serious effort to express their

answers in clear and coherent English and that the marks awarded for the quality of written

communication had shown some improvement. Even so, the incorrect use of technical

vocabulary frequently limits the mark that can be awarded to one out of the possible two.

Question 1

In part (a), candidates often wrote about the principal features of a stationary wave (nodes

and antinodes) instead of addressing the conditions required for the formation of a stationary

wave. It was expected that there would be reference to the overlapping of two progressive

waves having the same frequency, similar amplitudes and equal but opposite velocities.

Part (b) usually produced good responses, with the numerical values for wavelength and

frequency in parts (i) and (ii) both correct. Candidates were sometimes troubled more by part

(iii). Most seemed to realise that the period would be 4.0 ms and that 3.0 ms implied three-

quarters of something. By no means all the candidates recognised that ¾ of an oscillation

would put the string in the undisplaced position. Many candidates turned their thoughts to a

progressive wave, and went on to draw such a wave - which had moved ¾ of a wavelength to

the right in their diagram.

Question 2

Units of the various physical quantities related to fields and the scalar/vector nature of them,

are generally not well known by the candidates. Part (a) showed that the 2004 cohort were no

better than their predecessors. Six correct entries in the table were required for three marks,


��20

and it was very rare for all three to be awarded. The unit of N m kg�1

was accepted as an

alternative to J kg-1

for gravitational potential, but

candidates regularly put N kg-1

in the table. The unit of electric field strength was

known better, and that of magnetic flux density was usually shown correctly. Candidates

often resorted to guesswork when completing the second column of the table. Many did not

appreciate that the concept of potential arises from energy considerations and that it is

therefore a scalar quantity, whilst the other two quantities are force-related and therefore

vectors.

Completely correct answers to part (b) were encountered in many of the scripts. Since the

unit of E had already been tested in the table in part (a), no penalty was imposed for wrong or

missing units in the answer to part (b)(i). A worrying error, made by a significant minority of

the candidates, was to equate the electric force on the particle to its mass, rather than to its

weight.

Question 3

This question was intended as a straightforward test of the “simple experimental phenomena”

of electromagnetic induction and Lenz’s law, as required by Section 13.4.4 of the

Specification. It is recognised that most A level candidates have difficulty with these topics

and examiners were not very surprised by the many relatively weak answers that were

written. Partial (or superficial) understanding of the phenomena appeared to be the main

obstacle to progress. For example, in part (a) almost all candidates appreciated that the

ammeter needle would deflect, but relatively few saw that it would move one way, and then

the other way, before returning to zero. In this part, examiners sometimes wondered what

was going through the minds of candidates who wrote things such as “the current through the

ammeter would increase, and then return to its normal value”. Perhaps this suggests that

these students had never previously encountered a centre zero instrument. Inappropriate use

of English also handicapped some candidates in part (a) – typical of which were answers that

began with “the ammeter moves to the right”.

Failure to address the question was the main difficulty encountered in most answers to part

(b). Instead of stating clearly that the acceleration of the magnet decreased, candidates

usually preferred to resort to woolly descriptions of the effect on the motion of the magnet.

Responses such as “the magnet slows down” and “it decelerates” were rejected. “The

acceleration slows down” was not a preferred response but it was accepted. The major

problem in part (b)(ii) was the failure of candidates to read the question properly: this was

about the effect on the acceleration of the magnet as it left the coil, not after it had left the

coil. Consequently a large number of candidates followed a broadly correct deduction in (i)

by an incorrect one in (ii): they thought that the acceleration would increase. The two

explanation marks in part (b) escaped all but the most knowledgeable candidates. Some

understanding of what was induced and why, was almost a prerequisite to progress here.

Bald reference to Lenz’s law was not considered to be adequate.

Even after presenting indifferent answers to the earlier parts of this question, many candidates

salvaged most of the three marks in part (c). Most appreciated that an incomplete circuit

meant that no current could flow, but many candidates wrongly thought that the missing

ammeter would also prevent the induction of an emf.


�� 21

Question 4

The mathematical competence of the majority of candidates in this question was much better

than has been seen in several recent papers and full marks were frequently awarded. Previous

reports have emphasised that ½ CV2 is a safer route to the energy of a capacitor than ½ QV,

and in part (a) the message appeared to have got through to the candidates. In part (b) the

main problems appeared to be with the meaning of micro in �F and of kilo in k�; the unit of

time constant was expected to be shown as s and not �F.

The exponential decay equation was usually used correctly in part (c), where approaches via

Q = Q0 e-t/RC

and V = V0 e-t/RC

were equally valid. Only a tiny minority of the candidates

attempted any other approach and almost all of them were wrong.

Units 5-9: PHAP: Practical

General Comments

Relatively few of the candidates appeared to be re-sitting the examination and, as in the

previous examinations, the bulk of the entry was made up from a few centres with large

numbers of candidates. The number entered was similar to that in each of the previous

Spring examinations and although there remains a significant range of ability in the entry, the

impression gained was that the number of very weak candidates was smaller than before.

The mean mark was one higher than that produced in Spring 2003 when many candidates

struggled with question 1. This time, candidates found the planning question much more to

their liking although this improvement was slightly offset by a more challenging second

question. When compared with Spring 2002, the current candidates performed slightly better

in question 1 and slightly worse in question 2 to produce an almost identical overall mean

mark.

All the assessment objectives provided similar discrimination and when a large sample of the

entry was analysed, every mark in the ranges for AO3a (Planning) and for AO3d (Evaluating)

was utilised in the distribution. All but one mark in each of the distributions for AO3b and

AO3c was utilised. It was interesting to find that for a typical A grade and E grade

candidates alike, the fraction of the total mark obtained in each of the four assessment

objectives was strikingly similar. In contrast to previous examinations, few of the weaker

candidates gained the majority of their marks in AO3b and AO3c (Evaluating).

There was significant variation in the standard of presentation in the scripts but most

candidates managed to say as much as they felt necessary about question 1 without resorting

to supplementary sheets. There was less opportunity for extended writing in AO3d than in

previous examinations but this did not prevent some candidates departing from, or

completely missing, the point of the question. It seemed that, as in previous examinations,

candidates had not taken sufficient care in reading the question before starting their answer.

Some candidates lack a competent scientific vocabulary; the use of ‘ampage’ rather than

‘current’ and ‘voltage flowing’ rather than ‘across’ betrayed their lack of expertise.

However, others have become quite well versed in the terminology of practical investigation;

‘dependent variable’ cropping up frequently as did ‘anomalous’ (albeit in a bewildering range

of spellings).


��22

Graphical work is significantly better at A2 than at AS and in a small number of cases this

was implausibly good: it was easily discovered that these candidates had invented their

results. Candidates should understand that the falsification of data is easily discovered and in

such cases the penalty is severe.

A majority of candidates failed to gain one or both of the significant figure marks in AO3b

because they failed to record their x values to the nearest millimetre as required and because

the derived (x2) data was given to 2 and not 3 significant figures. The thinking seemed to be

that because they, in the course of the experiment, ‘set’ the x value to a convenient value, e.g.

40, 50, 60 cm etc., then these data could logically be recorded to the nearest centimetre.

Candidates should understand that data, whether for the dependent or independent variable,

should be recorded in a way that is consistent and appropriate to the method of measurement

being employed – in this case, a distance read between two points on a metre ruler calibrated

in millimetres.

A2 candidates proved to be generally dependable with mathematical processing. The

elevation of the period, T, to the fourth power (and the reverse process when determining TS

in (e)(i) was reliably done by all. Many, having chosen scales for their graphs that prevented

a direct reading of the intercept being made, were happy to use algebra instead, although

some forgot that their result for G should have a negative value.

The candidates appeared to have had sufficient time to complete both parts of the

examination and in instances where parts of questions were missing, it appeared that lack of

practice on the part of the candidate was the cause.

Question 1

Candidates were presented with a scenario in which an aluminium ring, placed over a vertical

soft iron rod, fell through a magnetic field produced by a coil surrounding the rod. They

were told that when an alternating current was passed through the coil, the time that the ring

took to fall through the magnetic field increased slightly. They were required to describe a

method of investigating how this small change in transit time might be affected if some

measurable change was made to the apparatus.

Although most candidates seemed to appreciate what was going on and had useful and

usually correct ideas about what could be accomplished, there were some oddities about

many of the answers seen. A significant number failed to take account of the clue given that

the transit time was only slightly increased and described hand-held timing measurements

that could not achieve successful results. Some, it seemed, are persuaded by the fact that

stopwatches record times to 0.01 s as valediction for

claiming this as the precision of the instrument. Other candidates appear to have great

confidence in any instrument that is fitted with a digital display (this point being made by

several in relation to the ammeter they intended to use).

Many diagrams the candidates provided did little or nothing to add to the information already

given in the question paper; some diagrams did more harm than good by including incorrect

circuits that would prevent the experiment from working as described (e.g. a voltmeter in

series with the coil). The most common circuit diagram error was the incorrect

representation of the ac power supply.


�� 23

To earn one of the three possible strategy marks, candidates had to identify from a wide

choice one variable that could affect the transit time of the ring. While adjusting the current

was a clear favourite for the majority, others chose to vary the number of turns on the coil,

the frequency of the ac or the thickness of the aluminium ring. Sadly some, in their

enthusiasm to communicate, forgot to vary anything at all or varied more than one thing at a

time.

Given that the situation hinged around the change in the transit time caused by the current, a

strategy mark was given if candidates mentioned that (as a means of comparison) the time

was measured with zero current, but relatively few made this point. The third mark was

awarded for some explanation of how the results would be analysed to discover whether a

link had been established between variable and transit time. Most candidates suggested the

data be shown in graphical form and providing some justification for this step was given, the

mark was awarded. Although not required, some candidates made a prediction about the

outcome: many felt that direct proportionality between current and transit time was

guaranteed but others confidently asserted that these variables would be linked with an

inverse relationship.

Marks were awarded for performing some suitable electrical measurement (usually current

with an ammeter) provided the circuit shown in any diagram would work. This mark was

awarded whether current was a variable or a control factor (e.g. in the case where the number

of turns on the coil was to be changed). If the frequency of the ac was to be varied a cro or

data logger was required. To measure the transit time, two light gates and a data logger were

expected; the idea that light gates could be connected to a ‘computer’ was not given full

credit. Some candidates described arrangements similar to that used to measure the

acceleration of freefall, apparently ignorant of the fact that an aluminium ring could not be

held in place by an electromagnet.

Three marks were available for identifying factors that should be controlled. Two of these

were to do with the interaction between the ring and the electromagnetic field around the coil:

if, for example, the candidates’ investigation involved varying the current, then the control

factors could be the number of turns on the coil and the frequency of the alternating current.

Another mark was awarded for identifying a control factor that made the timing a fair test:

candidates rarely said enough to give a completely accurate description of what should be

done but this point was marked generously with credit given for saying that the same stop and

start points were used or that the ring was released from the same height. Candidates

generally scored at least one, often two, but rarely three of these marks.

Marks for procedures and difficulties were infrequently awarded. Those who advocated hand-

held timing methods were given no credit for saying that repeating and averaging could

improve their results. Similarly, no credit was given for the suggestion that the reliability of

hand-held timings are improved by getting several people to collaborate in the exercise.

Marks were awarded if candidates suggested that extending the transit time by using a longer

coil/rod would reduce uncertainty. Details such as ensuring that the ring fell smoothly and

checking the coil and rod were vertical were also given credit.


��24

Question 2

Candidates were required to investigate how the period of a V-shaped pendulum depended on

the horizontal separation between the upper ends of the supporting strings. In contrast to the

observation in the previous report that many candidates seemed to have been short on

experience with shm exercises, this group fared better in performing their experiment.

However, the candidates found each section of the question testing in other ways and the

mean mark was slightly below that for each of the previous examinations.

In AO3b (parts (a), (b) and (c)), at least one and often two marks were withheld for recording

data to an inappropriate number of significant figures. Many candidates also failed to make x

measurements over a sufficiently wide range (at least 30.0 cm was required). The quality

mark was awarded if four of the five plotted points were close to the line and with most

timing, sufficient cycles to determine the period, T, (at least 20 or 20 were expected); this

mark was frequently awarded. The tabulation mark was given except in the isolated

instances where nT had been confused with T.

Candidates proved reliable in calculating the derived data sets and the graph and its analysis

(assessing AO3c) was generally sound. Some missed or gave incorrect units in labelling the

axes and there were the usual crop of scales that were compressed to include the origin.

Many forgot to record the gradient as being negative but the numerical answer was often in

the range 3.90 to 4.20, for which full credit could be given Candidates were not penalised for

any missing or incorrect units with their answer for G.

In part (e) (assessing AO3d) candidates were required to find the period of the pendulum for

which the horizontal separation of the strings was zero, a task to which nearly all proved

equal. Where the intercept was not directly obtainable, the use of algebra proved an

acceptable alternative and most were able to deduce a result for TS between 1.35 s and 1.60 s,

as expected. Many candidates knew the expression for the period of a simple pendulum (or

found it on the data sheet) and were usually able to obtain a result for �S that was in close

agreement with that for TS. Exceptionally, some candidates mixed units on substituting data

into the expression but it was unusual to find candidates who could make no progress with

this part.

In (e)(iii) some overlooked the information contained in the question that they were to

assume the percentage errors in T and x were the same and wrote instead about the

procedures they had followed to measure each variable. Such discussions generally

persuaded them that the error in x was the larger. Most though, saw that by raising T to the

fourth power (with x only raised to the second power) it would be the error in the period that

would contribute most towards the uncertainty in TS.


�� 25

Units 5 - 9: PHAC: Coursework

In most cases Centres used investigations which were appropriate, allowing their candidates

access to the full range of assessment criteria. Experiments on simple harmonic motion,

optical experiments on lenses and charging/discharging capacitors were the most popular and

these proved to be successful in allowing a full range of marks to be achieved.

The general comments on presentation of coursework and issues raised by moderators are the

same as those made on the AS work. Please refer to the detailed comments which appear on

pages 12 - 14 of this report.

Units 5 - 9: PHA5/W - PHA9/W: Section A : Nuclear Instability

Section A of Units 5 - 9 consists of a question on nuclear instability and is common to all

these units.

The majority of candidates understood the requirements of part (a) and were able to give

three arrows as a single route, but a significant number did not know the correct direction of

both types of decay. Horizontal and vertical arrows were commonly seen. A common

mistake was an apparent interpretation of the N on the vertical axis to mean nucleon number

instead of neutron number, as the question stated. Several candidates had very little idea how

to proceed and drew random lines which finished well away from the daughter nucleus.

Part (b), where two equations had to be completed was not well done with few candidates

scoring full marks and many scoring zero. The Ni nuclide often appeared as Cu, X or Y,

frequently with incorrect values in the subscript and/or superscript and occasionally with

different values in the decay mode. Weaker candidates often put the electron on the wrong

side of the decay equation. Neutrinos appeared in most answers, but most frequently as a

neutrino in one decay mode and an antineutrino in the other.

particles were the choice of the great majority of candidates for the scattering particles in

part (c) and for many candidates this was their only mark for this section. For most

candidates, the requirement to describe the main physical principle of the scattering process

was interpreted as ‘write as much as you can about Rutherford’s scattering experiment’,

resulting in answers which were imprecise and demonstrated little more knowledge or

understanding than that covered at GCSE. The idea that the experiment gave an upper limit

for the nuclear radius was missed by nearly all candidates. The small minority of candidates

who described electron diffraction by the nucleus usually answered the question well,

demonstrating appropriate knowledge about the intensity minimum and the information

gained from it. These candidates seemed to have a deeper understanding of the experiment,

perhaps due to the fact that this was a new situation which had been taught in more detail at

this level.


��26

Unit 5: PHA5/W: Section B : Astrophysics Option

General Comments:

Most candidates were able to attempt all the questions and full marks were achieved in each

question. Mathematical problems were generally answered well, although marks were lost

for failing to understand which units should be used for some of the physical quantities.

Answers requiring more extended writing tended to produce more variable responses. Often,

full marks were missed due to lack of detail, or irrelevant information. More care should be

taken to learn the important features of different astronomical phenomena. Many candidates

were able to score both marks for their quality of written communication.

Question 2

This question was generally very well answered with many candidates scoring high marks.

In part (i) most candidates correctly identified the two required properties of the image,

although several repeated the question by stating that the image was magnified. Another

common error was stating the image to be virtual. This last error would then be carried

forward to part (ii).

The ray diagrams drawn in part (ii) showed a big improvement in their clarity compared with

those of previous years. Centres had clearly acted on the comments in previous reports and

insisted that their candidates used a ruler and took care in drawing diagrams. A clear

misconception with many candidates is the position of the principal focus. It was commonly

labelled where the two rays crossed i.e. at the image. This error is probably due to the fact

that the concept is often introduced by drawing parallel rays entering the lens, so that the

image and principal focus coincide and candidates fail to recognise the special nature of the

situation in the question. Candidates should be alerted to this mistake.

In part (iii) most candidates substituted correct values into the lens formula and calculated the

lens power correctly. The most common error was associated with the unit, with many

candidates continuing to write watt as the unit of lens power.

Question 3

Many candidates achieved very good marks in this question, although very few obtained the

maximum available. In part (a) the mark for the definition of the light year was gained by

virtually all candidates, although some failed to express themselves sufficiently clearly. Very

occasionally answers which suggested that a light year was a measure of time rather than

distance were seen. By contrast, very few candidates were awarded the mark for stating what

is meant by the parsec. This is clearly on the specification although trigonometric parallax is

not longer required. The best answers stated the relationship between the angle, the AU and

the parsec, and included a diagram to make it absolutely clear.

A calculation using apparent and absolute magnitude is a common feature of this paper and

most candidates responded well to this example in part (b). However, far too many failed to

convert the distance (given in light years) into parsec before making the substitution in the

equation. The use of incorrect units was a common feature in the paper this year. Some

candidates mixed up the apparent and absolute magnitudes. This was treated as a physics

error and was therefore heavily penalised. In part (ii) most candidates correctly identified


�� 27

that spectral class A is hotter than spectral class G. The best candidates justified their

answers by quoting the OBAFGKM range, giving typical temperatures for the two classes.

Part (iii) required more careful justification. There was some clear confusion as to whether

the stars were the same brightness. The best answers correctly identified star A as the

smaller, comparing the temperatures of the two stars, and using Stefan’s Law to justify the

answer.

Questions on resolving power are another common feature of this option. In part (c) the

correct expression was generally used but most candidates lost a mark by not converting the

angle quoted into radians before substitution.

Question 4

This was a question that many candidates found difficult, with only a few scoring maximum,

or near maximum marks. In part (a) (i) awarding marks to the black body radiation curve for

the Sun was often generous, but there were many candidates who had no idea of the shape or

the main feature of the curve. Examiners were looking for a steep curve on the left hand side

of the peak, with a much more gradual curve towards zero on the right hand side. Good

answers showed an intercept on the low frequency side of a fairly narrow peak. There were

many different positions given in part (ii) for the region of ultraviolet absorption. Candidates

were rewarded for marking a region to the left of the peak, within the overall curve. In part

(iii) the fairly common answer that absorption was due to the ozone (frequently spelt o-zone)

seems to suggest that some candidates believe that this is a region of the atmosphere rather

than a gas. Benefit of the doubt however was given for this answer. Many candidates in part

(iv) could not link ultraviolet absorption with the effect on the wavelength of the peak and

therefore on the calculated temperature using Wien’s Law. There was much evidence that

candidates were not familiar with the problem. Many discussed, for example, the absorption

of the light by the atmosphere of the star. Some credit was given for answers which could

explain why the absorption of light could suggest the star was cooler, without reference to

Wien’s Law.

The fairly straightforward calculation in part (b)(i) was usually answered well, although there

was evidence of some confusion between the prefixes G and M in the frequency values. The

identification of the Doppler effect in part (ii) was an easy mark that was gained by almost all

candidates. The calculation in part (iii) identified more difficulties. Although the process

actually involves a double Doppler shift because the Moon acts both as a receiver and a

source (reflecting the received signal) this was ignored when marking and full marks were

awarded if candidates only calculated the single shift. There was much confusion over the

use of the equation however. Some candidates apparently believed that the � in the equation

was a variable. Very few candidates answered fully and stated that the increase in frequency

meant that the Moon and Earth were getting closer. Some errors led to answers at or greater

than the speed of light. There was no evidence of candidates being wary of these answers or

suggestions that they may have made a mistake. Credit was not awarded for consequential

errors leading to these answers as candidates should realise, particularly with speed

calculations, that when an answer is ridiculous or impossible they should be encouraged to

comment on it.


��28

Question 5

Unfortunately this was incorrectly labelled as question 4 in the paper but this printing error

did not cause candidates any problems. Almost all candidates managed to write something

about the Big Bang. Those who gained no credit included candidates who described the

processes in a supernova. The expansion of the Universe also caused problems with some

students. It was commonly suggested that everything was expanding and that Hubble’s red

shift was measured for stars, with no mention of galaxies. Background radiation was often

given as evidence for the Big Bang, but this was not given credit unless it was made clear

what form this radiation takes.

The inclusion of this subject in the Specification gives candidates the opportunity to read

about one of the most important theories in modern cosmology. Unfortunately too many

answers were vague and ambiguous and suggested little more knowledge or understanding

than that of the general public.

Unit 6 : PHA6/W : Section B : Medical Physics Option

General Comments

Although the examiners considered all the questions to be accessible only a few candidates

gained high marks. Question 2 required a ray diagram to be drawn. This is the first time for

a few years that such a question has been set and it appeared to catch the candidates by

surprise since, in general, the diagrams were very poor.

Question 2

This question produced the poorest answers in the whole paper and it was clear that many

candidates had little real knowledge of the situation outlined in the question. In part (a) the

large majority of candidates failed to appreciate that the image was virtual and did not apply

the correct convention in the calculation involving the lens formula. More candidates worked

out the magnification correctly, but a noticeable number wrongly used object distance

divided by image distance.

In part (b) only two correct diagrams were seen. Candidates appeared to have very little idea

of how to construct a ray diagram and of those that did they failed to realise the relevance of

the virtual image.

The best answers appeared in part (c)(i). In part (ii), clear thinking was missing in most of

the answers submitted. Even allowing for an incorrect answer in part (a)(i) to be carried

forward, very few candidates produced a correct answer. Many were unable to even start the

calculation and of those that did, the majority stated that the aided far point would still be at

infinity.


�� 29

Question 3

Several candidates gained full marks for this question. In part (a), many lost the first mark by

defining intensity in terms of energy instead of energy per second or power. Many

candidates gave a correct explanation of attenuation but a common misconception was that

attenuation was caused by the spreading of a wave from a point source according to the

inverse square law.

In part (b), although many candidates carried out the calculation correctly a common error

arose from the fact that the units were not read carefully enough and watts was used as the

unit of I0 instead of the given mW.

Question 4

Candidates provided good answers to this question and it earned the highest marks on the

paper. In part (a) most candidates were able to describe the action of the heart and full marks

were awarded quite often. Marks were lost when candidates were unable to express their

ideas clearly and occasionally four steps were described as atrium to ventricule to atrium to

ventricule.

Answers to part (b) also saw many full marks being awarded but marks were lost for

including wrong answers alongside the correct ones, e.g. in part (i) stating that both

potassium and sodium ions entered the membrane.

Question 5

Although a number of candidates gained full marks, this question proved to be difficult for

some. Answers to part (a) often lacked the clarity needed to be awarded the allocated marks

and usually candidates were only awarded one or two marks of the possible three. A number

of candidates did not really understand what was required by the question and tried to answer

in terms of an image intensifier or intensifying screens. Some candidates even discussed the

use of a grid to enhance the picture by reducing scattered X-rays reaching the film.

It was very pleasing to find that the calculation in part (b) was carried out correctly in a

number of cases. Some candidates failed to rearrange the exponential equation correctly but

they appeared to be fewer in number than in previous years.


��30

Unit 7: PHA7/W: Section B: Applied Physics Option

General Comments

It was clear that almost all candidates had been well prepared for this paper and the quality of

answers in most cases ranged from good to excellent. Almost all candidates attempted every

question and there was no evidence of a shortage of time on the paper. With few exceptions,

the standard of English and the presentation were good. There were few problems with the

use of units in some answers, but more candidates than is usual in this January paper were

penalised for the use of an inappropriate number of significant figures in a numerical answer.

Question 2

Most candidates found this question straightforward and many scored full marks. In part

(a)(i), the unit of torque was almost always present and correct; an unexpected and

remarkable improvement on previous papers. In part (b), some candidates worked out a

value for the moment of inertia of one tube only rather than the eight in use and rather more

failed to add to this the moment of inertia of the centrifuge itself to find the total moment of

inertia. Part (c) was almost always done well and usually completely correctly.

Question 3

Almost all candidates answered this question very well, with most scoring full marks in part

(a) and many scoring at least two of the available three marks in part (b). In part (b)(i), the

correct equation was almost always seen but a value of 12 kJ was

occasionally used in place of the correct value of 36 kJ for the energy remaining after the

stamping operation. The unit of angular impulse was sometimes omitted or incorrect in part

(ii). Part (iii) was almost always correct, allowing for an error carried forward from parts (i)

and/or (ii).

Question 4

Most candidates knew the physics relating to the behaviour of gases in adiabatic compression

and many achieved full marks for this question. Almost the only difficulty experienced by

candidates was the calculation of the volume of gas before and after compression; every

mistake which could be made was made. As far as possible, an error of this kind is treated as

an arithmetic error and penalised only once. Occasionally, however, the same or a similar

error in parts (i), (ii) and (iii) led to absurdly high or low values of pressure and temperature

which could not be awarded a mark.

Question 5

Candidates almost always arrived at the correct answer to part (a), but some gave the unit as J

or kJ and very many expressed the answer to six or seven significant figures. In part (b)(i),

the majority of candidates went through the process of finding the area enclosed by the loop

quite convincingly, although a number did not attempt to calculate the energy equivalent to

the area contained by one square. Few candidates remembered that, in a four-stroke engine,

two revolutions of the output shaft correspond to one cycle. Full marks for this section were

very rarely seen.


�� 31

In part (c)(i), the actual output power at the crankshaft is lower than that suggested by the

indicator diagram because some of the available power is used to open and close valves, draw

gas into the engine and expel it, do work against friction in the engine bearings and between

the piston and the cylinder, drive the oil and water pumps and so on. It has nothing to do

with heat losses to the surroundings (the almost universal answer) or thermodynamic

efficiency (a common answer); these are certainly largely responsible for the overall low

efficiency of the engine, calculated in part (ii), but that was not what the question asked.

Most candidates were awarded the mark for suggesting ‘friction’, but those who did not make

it clear that the friction was associated with the engine itself were not awarded the mark. Part

(ii) was usually correct.

Unit 8: PHA8/W: Section B : Turning Points in Physics Option

General Comments

Most candidates were able to attempt every question on the paper. Calculations formed a

smaller part of the paper than in previous years. The best candidates did well on the

calculations and straightforward descriptions and explanations. More complicated

descriptions provided challenges which produced a mixture of good responses and poor

responses from good candidates throughout. Poor descriptions often revealed a failure to

plan and write a coherent answer. Weaker candidates tended to pick up most of their marks

on the calculations and through knowledge of assorted facts in parts of the descriptive

questions.

Question 2

In part (a)(i), most candidates were aware that the wire needed to be heated in order to free

electrons from it but few referred to the kinetic energy gained by conduction electrons. In

part (ii), many candidates referred to ionisation of air molecules rather than electrons being

stopped or slowed down by air molecules. In part (iii), most candidates knew why the anode

needed to be at a positive potential.

Most candidates know how to calculate the gain of kinetic energy in part (b)(i) but many

candidates lost a mark as a result of a significant figure error. The calculation in part (ii) was

usually completed correctly.

Question 3

Relatively few good answers were seen in part (a). Most candidates mentioned that the

theory required an increase of speed of the corpuscles on entry to glass. Some candidates did

refer to an attractive force acting on the corpuscles. However, very few candidates were able

to give a satisfactory account of the effect on the velocity or momentum components of the

corpuscles. Those candidates who did provide a satisfactory account usually gave an

appropriate diagram to support their account.

In part (b)(i), a significant number of candidates often failed to state what each theory

predicted. In part (ii), most candidates scored both marks by giving an account in appropriate

terms of Young's double slits experiment.


��32

Question 4

Although most candidates knew in part (a) that electrons crossed the gap in the scanning

tunnelling microscope because of the wave nature of the electron, they usually referred to

tunnelling and probability rather than attenuation of the wave. Many candidates knew that

the probability of an electron crossing the gap was greater the narrower the gap. The best

candidates were able to explain satisfactorily why a potential difference was necessary

although many candidates considered the potential difference caused insulation breakdown

between the tip and the surface.

Very few good answers were seen in part (b). Most candidates knew that the tunnelling

current varied according to the gap width but few gave a clear answer in terms of a constant

current or the tip being at a constant height. Many candidates switched from constant current

to constant height, often as a result of confusion about feedback giving a constant gap width.

Some candidates failed to mention that the current or the tip height was monitored as the tip

was scanned across the surface.

Question 5

Very few candidates referred to Newton's laws or constant velocity in part (a). Some

candidates referred to examples in terms of constant speed without mentioning direction.

Most examples that gained credit referred to a simple example such as a free object inside an

aeroplane.

In part (b)(i), most candidates carried out the calculation correctly. Some, however, inserted

18 ns incorrectly into the time dilation equation. In part (ii), most candidates who scored

well, correctly used the distance and speed to calculate the time taken and then compared

their answer with the half-life in the laboratory frame of reference. There were candidates

who used the length contraction formula correctly and then made a comparison with the

distance calculated using an incorrect value of time from part (i).

Unit 9 : PHA9/W : Section B : Electronics Option

General Comments

Very few candidates were entered for this paper and thus any general comments concerning

the examination would not be pertinent. Although all the candidates attempted all of the

questions set, very few consistently scored high marks.

Question 2

Answers to this question were very disappointing and showed a lack of basic understanding

of the concepts involved. In parts (a)(i) and (ii) the majority of candidates applied the

potential divider equation directly to the supply voltage, ignoring the potential drop across the

two diodes. This obviously gave the wrong answer, but these candidates were given some

credit for the method of working and the answer was carried forward to part (ii), so it was

possible to gain some marks there.


�� 33

The majority of candidates failed to gain any marks in part (b). The idea that the whole of the

supply potential would be dropped across the reversed diode was beyond the candidates and 0

V was the usual answer for the pd between B and C.

Question 3

Part (a) gave candidates the opportunity to describe how a circuit worked and produced the

given output waveform. Some good attempts were offered but only a few gained full marks.

The purpose of the diode in the circuit was largely ignored, candidates not realising that it

prevented flow of charge backwards from the capacitor when the input voltage dropped to 0

V. Very few mentioned that the discharge curve was exponential in nature.

It was good to note in part (b) that most of the candidates were aware that the time of

discharge was � 5RC. However, after this promising start, silly mistakes were made in the

calculation through using incorrect values of the time base and reading inaccurate values

from the grid.

Question 4

This was the best answered question on the paper and it was not uncommon for candidates to

gain full marks. Again, it was carelessness which produced a loss of marks. Part (a) was

answered correctly by almost all candidates. The value of pd obtained in part (a) together

with the resistance of the thermistor at 0 �C were used

correctly by the majority of candidates to obtain the value of R1.

The common mistake in part (c) was to use the value of the given pd (2.0 V) as the pd across

the resistor R2 rather than that across the LED, thus giving the wrong value for R2. Allowing

the value of R2 to be carried forward enabled most candidates to calculate the power

dissipated in this resistor.

Several candidates made careless mistakes in part (d) when deciding on the resistor to be

chosen from the E24 series. Several chose a value lower than that calculated in part (c) and

others, when their calculated value happened to be included in the E24 series, chose a

different value.

Question 5

This question realised better answers than when a similar question was asked previously. It

was pleasing to find that several candidates gave an accurate description of the action of the

transistor and gained full marks. The accounts of the remainder suffered from a lack of

clarity in the answers. Part (b) proved to be a very easy last section to the paper and nearly

all candidates drew the diode in the correct position and in the correct direction.


��34

Unit 10: PA10: The Synoptic Unit

General Comments

Most candidates scored marks in every question in the paper. The straightforward

calculations were usually done reasonably well and some of the best candidates responded

well to the more challenging calculations. Although most candidates scored some marks on

most of the descriptive answers, such answers were often marred by lack of essential

knowledge or by failure to read the question carefully. Some candidates answered all the

questions well, although few candidates were able to provide good descriptive answers in all

such questions. The graph question enabled very weak candidates to score some marks

through data handling and graph plotting. Units were generally correctly given. The quality

of written communication was generally adequate although very few candidates were able to

write continuous prose with confidence.

Question 1

The majority of candidates were able to calculate the electrical energy supplied to the kettle

in part (i) and the heat energy supplied to the water in part (ii). Significant figure penalties

were imposed in part (ii). In part (iii), some candidates considered that the kettle cable

became heated because of its resistance and many missed the point that there was heat loss

from the kettle to the surroundings.

In part (b) many candidates scored well, particularly in part (i). Candidates often lost a mark

in part (ii) through an incorrect calculation of the cross-sectional area or by using an incorrect

formula for the cross-sectional area. Weak candidates often penalised themselves heavily as

a result of being unable to rearrange the resistivity equation correctly.

Question 2

There were some good answers to part (a) which usually referred to the increased impact time

causing a lower rate of change of momentum or a lower deceleration and therefore a reduced

force. Many candidates correctly gave the relevant equation. Weaker candidates sometimes

thought the change of momentum was reduced by the use of an air bag. Candidates who

referred to the loss of energy of the driver often failed to mention that the energy lost was

kinetic energy and they usually failed to mention as well that the air bag increased the

distance over which the kinetic energy was lost.

Many candidates scored both marks in part (b). Some candidates did lose a mark as a result

of confusion between the initial and final velocity of the driver.

Question 3

In part (a), few candidates scored well. Many were unable to select the relevant data in order

to answer each part. In part (iii), those who answered the question correctly usually

calculated and used the maximum speed of the pendulum. Candidates who attempted to use

the equation for displacement in terms of time usually failed to insert the correct value of the

time in the equation.


�� 35

The majority of candidates made very little progress with part (b), mainly as a result of using

1.0 V instead of 0.3 V for the pd across the resistor. Others calculated the current incorrectly

by dividing the given resistance into 1.3 V instead of 1.0 V. Few candidates attempted to use

the potential divider equation and those who did usually inserted incorrect values of pd. Few

candidates were able to answer both parts of this question adequately.

Question 4

Many candidates scored well in parts (a)(i) and (ii), although some were unable to use the

relevant equations correctly. Almost all candidates were aware that the light ray was totally

internally reflected at R in part (iii) although a few failed to mention the subsequent internal

reflections of the ray.

In part (b) most candidates scored well, giving a correct ray diagram as well as a correct

comparison and reason for the different times taken by the light pulses to travel. Some

candidates lost a mark by drawing the refraction at Q incorrectly.

Question 5

In part (a) many candidates failed to read the question correctly and did not realise that two

sets of measurements meant two pairs of measurements. Consequently, many candidates

used the values of x and t for the first image only and obtained an unacceptable answer. Few

candidates provided a suitably valid reason for their choice of data. Many candidates

considered a valid reason to be the constant value of the horizontal component of velocity.

Only the best candidates used the difference between the first and last values and also

provided a valid reason.

Some candidates failed to give their answers in part (b) to the same number of significant

figures as the data provided. In part (ii), most candidates were aware of the correct graph to

plot and were able to produce the necessary straight line graph. However many candidates

lost a mark through an inappropriate scale for y/t. In part (iii), the majority of candidates

were able to determine the correct values of u and k, usually providing clear indications on

the graph for the gradient calculation.

Many candidates failed to score a single mark in part (c). Some did know the physical

significance of u but almost all failed to realise the significance of k. Even the best

candidates were unable to relate the given equation in part (b) to their knowledge of projectile

motion.

Very few candidates realised in part (d) that they were expected to apply their knowledge of

vectors and use appropriate values from parts (a) and (b).

Question 6

Many candidates misread part (a) and thought that the transmitter was rotated in such a way

that the direction of the beam became perpendicular to the line XY. In fact, few candidates

realised that the question concerned polarisation. Those who did realise this, attempted an

answer in polarisation terms but often thought that the action of rotating the transmitter

polarised the waves. Very few candidates realised that the receiver signal become zero

because the plane of polarisation of the microwaves had been turned through 90�.


��36

In part (b), most candidates calculated the frequency correctly and in part (ii) many

candidates knew that there were nodes where the food would be uncooked, although some

failed to mention that the nodes were points of zero intensity or energy.

Question 7

Only the better candidates were able to give the correct equations for E and V in part (a)(i)

and were thus able to produce the required relationship between them. In part (ii), many

candidates lost a mark as a result of inappropriate units.

In part (b), almost all candidates were able to calculate the peak potential correctly. It was

unfortunate that many candidates calculated the minimum radius in part (ii) but failed to give

the minimum diameter as required. Weaker candidates often lost a mark through an incorrect

rearrangement of the given equation or by the use of incorrect units.

Question 8

In part (a)(i), many candidates failed to give the correct proton number of the product isotope.

Some candidates saw the negative charge symbol of the particle as an invitation to subtract

one from the mass number of 40K . In part (ii), most candidates gained marks for the W

�

particle, the �

particle and the antineutrino. However, many Feynman diagrams showed the

isotopes instead of the proton and the neutron, or reversed the positions of the neutron and the

proton.

Many candidates failed again to give the correct proton number of the product isotope in

parts (b)(i) and (ii) and few candidates scored the mark for the W boson and the proton and

neutron. Many gave incorrect directions for the electron and neutrino arrows.

Relatively few candidates gave an adequate explanation in part (c). Most candidates knew

that nine potassium atoms had decayed for each argon atom present in the rock but few gave

an adequate explanation of why there were originally thirteen potassium atoms for every

argon atom. In part (ii), those candidates who knew that N = 4 and

N0 = 13 were usually able to make some progress in the calculation. The best

candidates correctly calculated the decay constant and used the relevant equation with

confidence to obtain the correct age of the sample.


�� 37

Mark Ranges and Award of Grades

Unit

Maximum

Mark

(Raw)

Maximum

Mark

(Scaled)

Mean

Mark

(Scaled)

Standard

Deviation

(Scaled)

PA01 50 50 31.1 11.3

PA02 50 50 32.6 10.0

PHA3/W – Written 50 50 30.4 11.0

PHA3/C – Coursework 30 30 21.5 5.5

PA3C - 80 51.9 14.1

PHA3/W – Written 50 50 32.1 10.4

PHA3/C – Practical 30 30 17.6 4.0

PA3P - 80 49.7 12.0

PA04 60 60 37.0 11.2

PHA5/W – Written 40 60 22.6 7.5


PA5C - 90 56.2 13.1

PHA5/W – Written 40 60 22.9 7.0

PHA5/P – Practical 30 30 16.6 4.6

PA5P - 90 51.2 12.9

PHA6/W – Written 40 60 19.4 5.7


PA6C - 90 55.1 9.6

PHA6/W – Written 40 60 21.6 6.3

PHA6/P – Practical 30 30 20.0 3.4

PA6P - 90 52.6 9.6


��38

PHA7/W – Written 40 60 26.8 7.9


PA7C - 90 64.5 15.7

PHA7/W – Written 40 60 23.0 4.0

PHA7/P – Practical 30 30 16.0 -

PA7P - 90 51.0 6.0

PHA8/W – Written 40 60 21.1 6.6


PA8C - 90 55.0 12.8

PHA8/W – Written 40 60 24.9 6.7

PHA8/P – Practical 30 30 18.1 4.3

PA8P - 90 55.7 12.7

PHA9/W – Written 40 60 20.4 4.4


PA9C - 90 53.2 6.7

PHA9/W – Written 40 60 20.8 5.1

PHA9/P – Practical 30 30 15.6 4.8

PA9P - 90 47.1 11.0

PA10 80 80 36.8 13.4

For units which contain only one component, scaled marks are the same as raw marks.


�� 39

PA01 Particles, Radiation and Quantum Phenomena

(4499 candidates)

GradeMax.

markA B C D E

Scaled Boundary Mark 50 39 34 29 25 21

Uniform Boundary Mark 90 72 63 54 45 36

PA02 Mechanics and Molecular Kinetic Theory

(3327 candidates)

GradeMax.

markA B C D E



PA3C Current Elasticity and Elastic Properties of Solids

Coursework

(698 candidates)

Max.mark

A B C D E

raw 50 40 35 30 25 21PHA3/W Boundary Mark

scaled 50 40 35 30 25 21

raw 30 25 22 19 16 13PHA3/C Boundary Mark

scaled 30 25 22 19 16 13

PA3C Scaled Boundary Mark 80 65 57 49 41 34

PA3C Uniform Boundary Mark 120 96 84 72 60 48


��40

PA3P Current Elasticity and Elastic Properties of Solids

Practical

(339 candidates)

Max.mark

A B C D E


scaled 50 40 35 30 25 21

raw 30 21 19 18 16 14PHA3/P Boundary Mark

scaled 30 21 19 18 16 14


PA3P Uniform Boundary Mark 120 96 84 72 60 48

PA04 Waves, Fields and Nuclear Energy

(2894 candidates)

GradeMax.mark

A B C D E




�� 41

PA5C Astrophysics Coursework

(318 candidates)

Max.mark

A B C D E


scaled 60 43 38 33 28 24


scaled 30 26 23 20 17 14



PA5P Astrophysics Practical

(104 candidates)

Max.

markA B C D E


scaled 60 43 38 33 29 24


scaled 30 21 19 17 15 14

PA5P Scaled Boundary Mark 90 64 57 50 44 38



��42

PA6C Medical Physics Coursework

(22 candidates)

Max.mark

A B C D E


scaled 60 42 37 32 28 24


scaled 30 26 23 20 17 14



PA6P Medical Physics Practical

(21 candidates)

Max.

markA B C D E


scaled 60 42 37 33 29 24


scaled 30 21 19 17 15 14




�� 43

PA7C Applied Physics Coursework

(146 candidates)

Max.mark

A B C D E


scaled 60 45 39 34 29 24


scaled 30 26 23 20 17 14



PA7P Applied Physics Practical

(2 candidates)

Max.

markA B C D E


scaled 60 45 40 35 30 24


scaled 30 21 19 17 15 14




��44

PA8C Turning Points in Physics Coursework

(78 candidates)

Max.mark

A B C D E


scaled 60 42 37 33 29 25


scaled 30 26 23 20 17 14



PA8P Turning Points in Physics Practical

(32 candidates)

Max.

markA B C D E


scaled 60 42 38 34 30 25


scaled 30 21 19 17 15 14




�� 45

PA9C Electronics Coursework

(5 candidates)

Max.mark

A B C D E


scaled 60 43 38 33 29 25


scaled 30 26 23 20 17 14



PA9P Electronics Practical

(13 candidates)

Max.

markA B C D E


scaled 60 43 38 34 30 25


scaled 30 21 19 17 15 14




��46

PA10 Synoptic Paper

(78 candidates)

GradeMax.

markA B C D E



Advanced Subsidiary award

Provisional statistics for the award (431 candidates)

A B C D E

Cumulative % 23.90 45.01 64.73 81.90 96.52

Advanced award

Provisional statistics for the award (32 candidates)

A B C D E

Cumulative % 6.25 37.50 71.88 81.25 93.75

Definitions

Boundary Mark: the minimum mark required by a candidate to qualify for a given grade.

Mean Mark: is the sum of all candidates’ marks divided by the number of candidates. In order to

compare mean marks for different components, the mean mark (scaled) should be expressed as a

percentage of the maximum mark (scaled).

Standard Deviation: a measure of the spread of candidates’ marks. In most components,

approximately two-thirds of all candidates lie in a range of plus or minus one standard deviation from

the mean, and approximately 95% of all candidates lie in a range of plus or minus two standard

deviations from the mean. In order to compare the standard deviations for different components, the

standard deviation (scaled) should be expressed as a percentage of the maximum mark (scaled).

Uniform Mark: a score on a standard scale which indicates a candidate’s performance. The lowest

uniform mark for grade A is always 80% of the maximum uniform mark for the unit, similarly grade

B is 70%, grade C is 60%, grade D is 50% and grade E is 40%. A candidate’s total scaled mark for

each unit is converted to a uniform mark and the uniform marks for the units which count towards the

AS or A-level qualification are added in order to determine the candidate’s overall grade.

gce january 2004 report on the examination - … 12,13/a level physics past papers... · report on...

Documents