PHYSICS PHYSICS EXAMINATIONS – 2007EXAMINATIONS – 2007

Bruce WalshBruce Walsh

REMINDERSREMINDERS CalculatorsCalculators

Study design and textbooksStudy design and textbooks

Examiners report Examiners report

VASS systemVASS system

SSMSSSMS

Exam format - detailed studiesExam format - detailed studies

JUNE EXAMINATIONJUNE EXAMINATION

STATISTICSSTATISTICS

6544 students6544 students

Mean = 99 = 55%Mean = 99 = 55%

Std dev = 41.5 = 23%Std dev = 41.5 = 23%

Number achieving 100% = 4Number achieving 100% = 4

GRADEGRADE MIN (/180)MIN (/180) MIN (%)MIN (%)

A+A+ 153153 8585

AA 137137 7676

B+B+ 121121 6767

BB 103103 5757

C+C+ 8484 4747

CC 6767 3737

D+D+ 5252 2929

DD 3838 2121

E+E+ 2727 1515

EE 2020 1111

ChallengingChallenging

Detailed studiesDetailed studies

Attempt ONE detailed study onlyAttempt ONE detailed study only

Explanations address specific question. – Explanations address specific question. – DiagramsDiagrams

Show workingShow working

GENERAL COMMENTSGENERAL COMMENTS

Converting unitsConverting units

Calculations – powers of 10Calculations – powers of 10 - raising to power eg. R- raising to power eg. R33

- simple mathematics- simple mathematics

Care reading scale on axesCare reading scale on axes

Multiple choice questionsMultiple choice questions

Illegible writingIllegible writing

PROBLEM AREASPROBLEM AREASMOTIONMOTION

Q2 Light lands directly below seatQ2 Light lands directly below seat

Q5 Determining Q5 Determining ΔΔpp

Q9, 10 In spring formulae x is Q9, 10 In spring formulae x is extension not total lengthextension not total length

Q11 Total energy is constantQ11 Total energy is constant

Q12 Difficulty with ratiosQ12 Difficulty with ratios

Q13 Mathematical difficulties with RQ13 Mathematical difficulties with R33 and Tand T22

Q14,15 Treat horiz and vert Q14,15 Treat horiz and vert components. Derived equations components. Derived equations caused confusioncaused confusion

ELECTRONICS & PHOTONICSELECTRONICS & PHOTONICS

Q1,2 Improving, but still difficult for Q1,2 Improving, but still difficult for studentsstudents

Q3 Few provided a clear answerQ3 Few provided a clear answer

Q9 Explanations unclearQ9 Explanations unclear

Q10,11 Intensity of light cannot go below Q10,11 Intensity of light cannot go below zero zero

RELATIVITYRELATIVITY

Q2 Many unable to determine speed Q2 Many unable to determine speed of soundof sound

Q8 Determining appropriate frame of Q8 Determining appropriate frame of referencereference

MATERIALS & STRUCTURESMATERIALS & STRUCTURES

Q2 TorquesQ2 Torques

Q4 Locating point of tensionQ4 Locating point of tension

Q8 Work = Area of graph x Volume. Many Q8 Work = Area of graph x Volume. Many forgot volumeforgot volume

Q10 Torque or triangle of forces or Q10 Torque or triangle of forces or resolution of forcesresolution of forces

FURTHER ELECTRONICSFURTHER ELECTRONICS

Q5 Time constant – 63% changeQ5 Time constant – 63% change

10 Increased I 10 Increased I increased voltage increased voltage drop drop OROR Decreased load Decreased load

decreased decreased and increased ripple and increased ripple

Q11 Regulator, increase transformer Q11 Regulator, increase transformer output, increase capacitor output, increase capacitor

NOVEMBER NOVEMBER EXAMINATIONEXAMINATION

STATISTICSSTATISTICS

6392 students6392 students

Mean = 110 = 61%Mean = 110 = 61%

Std dev = 43 = 24%Std dev = 43 = 24%

Number achieving 100% = 14Number achieving 100% = 14

GRADEGRADE MIN (/180)MIN (/180) MIN (%)MIN (%)

A+A+ 164164 9191

AA 150150 8383

B+B+ 134134 7474

BB 114114 6363

C+C+ 9292 5151

CC 7474 4141

D+D+ 5454 3030

DD 3636 2020

E+E+ 2020 1111

EE 1010 66

GENERAL COMMENTSGENERAL COMMENTS

Accessible paperAccessible paper

Detailed studiesDetailed studies

Illegible writingIllegible writing

Explanations must address specific Explanations must address specific questionquestion

Explanations – one mark per pointExplanations – one mark per point

Show workingShow working

Unit conversions, eg. cmUnit conversions, eg. cm22 to m to m22

Powers of 10 calculationsPowers of 10 calculations

Transformation of simple equations.Transformation of simple equations.

Direction of current flowDirection of current flow

Diffraction – Light & Matter c.f. SoundDiffraction – Light & Matter c.f. Sound

Diffraction patterns – gradual change Diffraction patterns – gradual change as as λλ/w ratio varies/w ratio varies

PROBLEM AREASPROBLEM AREASELECTRIC POWERELECTRIC POWER

Q1,2 Sketching magnetic fields.Q1,2 Sketching magnetic fields.

Q11 Series circuit ideasQ11 Series circuit ideas

Q12 More power consumed than Q12 More power consumed than supplied supplied

Q15 Explain application of Lenz’s lawQ15 Explain application of Lenz’s law

LIGHT and MATTERLIGHT and MATTER

Q5, 6 Diffraction patternsQ5, 6 Diffraction patterns

Q9 Not interference effectQ9 Not interference effect

Q10, 11 Behaviour of bound and free Q10, 11 Behaviour of bound and free electronselectrons

SYNCHROTRONSYNCHROTRON

Q4 Application of right hand ruleQ4 Application of right hand rule

Q11 Explanations poorQ11 Explanations poor

PHOTONICSPHOTONICS

Q6 Snell’s lawQ6 Snell’s law

Q7, 8 Relate effect to speed Q7, 8 Relate effect to speed variationsvariations

Q11 Internal reflection – gradual Q11 Internal reflection – gradual change in amountchange in amount

SOUNDSOUND

Q4 Resonance will be louderQ4 Resonance will be louder

Q7 Relate graph to frequency range Q7 Relate graph to frequency range of human voiceof human voice