Paper Reference(s)

5049/01Edexcel GCSEPhysicsP3 – Topics 5 and 6Wednesday 11 June 2008 – AfternoonTime: 1 hour

Materials required for examination Items included with question papersCalculator Nil

Instructions to CandidatesIn the boxes above, write your centre number, candidate number, your surname, initial(s) and signature.Check that you have the correct question paper.Answer ALL the questions. Write your answers in the spaces provided in this question paper.Do not use pencil. Use blue or black ink.Some questions must be answered with a cross in a box ( ). If you change your mind about an answer, put a line through the box ( ) and then mark your new answer with a cross ( ).Show all stages in any calculations and state the units. Calculators may be used.Include diagrams in your answers where these are helpful.

Information for CandidatesThe marks for individual questions and the parts of questions are shown in round brackets: e.g. (2).There are 9 questions in this question paper. The total mark for this paper is 60.There are 20 pages in this question paper. Any blank pages are indicated.

Advice to CandidatesYou are reminded of the importance of clear English and careful presentation in your answers.

Examiner’s use only

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Question Leave Number Blank

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Paper Reference

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This publication may be reproduced only in accordance with Edexcel Limited copyright policy. ©2008 Edexcel Limited.

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FORMULAEYou may find the following formulae useful.

pressuretemperature (Kelvin)

constant=

PT

PT

1

1

2

2=

pressure volumetemperature (Kelvin)

constant×=

P VT

P VT

1 1

1

2 2

2

×=

×

kinetic energy = electronic charge × accelerating voltage KE = e × V

work done = force × distance moved in the direction of the force W = F × s

power = work donetime taken

P Wt

=

frequency 1time period

=

fT

=1

intensity power of incident radiationarea

=

IPA

=

3

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TURN OVER FOR QUESTION 1

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1. (a) What is meant by basal metabolic rate?

.......................................................................................................................................(1)

(b) Alistair wants to increase his basal metabolic rate.

Tick all of the methods in the table below which would increase his basal metabolic rate.

method tick

sleep more

take more exercise

eat less

increase muscle to fat ratio

eat a more balanced diet(3)

(c) The table shows how Alistair’s body uses his daily energy input.

energy used in % of daily energy input

liver 19

brain 13

heart 5

kidneys 7

skeletal muscle 13

other systems 13

exercise 20

digestion 10

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(i) Complete the bar chart to show his daily energy use.

(1)

(ii) Which of the organs shown uses the least energy each day?

................................................................................................................................(1) Q1

(Total 6 marks)

perc

enta

ge o

f tot

alda

ily e

nerg

y us

e

20

0

10

liver brain heart kidneys skeletalmuscle

othersystems

exercise digestion

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2. Toni is revising her physics for an exam.

Her revision book has the following diagram of a cathode ray tube.

(a) Which letter shows

(i) the anode,

................................................................................................................................(1)

(ii) the cathode?

................................................................................................................................(1)

B

C

ED

F

F

6Vac GA

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(b) Complete the following sentences by putting a cross ( ) in the correct box.

anode.

(i) The electron beam is produced by the heated cathode.

screen.

air.

(ii) The inside of the tube contains a gas.

a vacuum.

light waves

(iii) When the electrons hit the screen, microwaves are produced.

radio waves

(iv) When the heater current is increased the number of electrons produced will

decrease.

increase.

stay the same.(4) Q2

(Total 6 marks)

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3. Toni’s notes are incomplete. She has the following neutron/proton graph for stable isotopes.

(a) Mark with an X on the diagram, the position of an unstable isotope which has too many neutrons.

(1)

(b) Complete the following sentences by putting a cross ( ) in the correct box.

α particles.

(i) An unstable isotope with too many neutrons decays by emitting β– particles.

β+ particles.

(1)

decreases.

(ii) During this decay the proton number increases.

stays the same.(1)

decreases.

(iii) During this decay the mass number increases.

stays the same.(1) Q3

(Total 4 marks)

number of neutrons

number of protons

1301201101009080706050403020100

10 20 30 40 50 60 70 80 90100

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4. (a) (i) Explain what is meant by refraction of light.

................................................................................................................................

................................................................................................................................(1)

(ii) Complete the following diagram to show the path of a ray of light through an optical fibre.

An accurate diagram is required.

(2)

(b) Max has suspected kidney stones. They cause him a lot of pain. His surgeon wants to use an endoscope to

examine the kidney stones.

(i) Explain how an endoscope works.

................................................................................................................................

................................................................................................................................

................................................................................................................................(2)

(ii) State why using an endoscope is better than using conventional open-wound surgery.

................................................................................................................................

................................................................................................................................(1) Q4

(Total 6 marks)

ray oflight

optical fibre

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5. Five years ago Sohanna was diagnosedwith breast cancer.

She had treatment and the cancer wentinto remission.

Recently her doctor told her that thecancer had spread into her neck bones.

She needs palliative therapy.

(a) Explain what is meant by palliative therapy.

.......................................................................................................................................

.......................................................................................................................................(1)

(b) Sohanna is given a course of external radiation therapy using a radioactive isotope. This lasts a few minutes on each of ten consecutive days.

(i) What is the effect of this type of radiation on living matter?

................................................................................................................................

................................................................................................................................(1)

(ii) Suggest a reason why Sohanna is treated over ten days instead of being given a large dose of radiation in one day.

................................................................................................................................

................................................................................................................................(1)

(iii) During the treatment the radiation source is rotated through a full circle around Sohanna’s neck.

Explain why this is better than keeping the source still.

................................................................................................................................

................................................................................................................................

................................................................................................................................(2)

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(c) The radiation physicist has to select a suitable source and radiation type for Sohanna’s treatment.

These are the sources and half-lives available.

source radiation type half-life

actinium-223 α 2.1 minutes

actinium-227 β 21.7 years

barium-129 γ 2.2 hours

barium-133 γ 10.5 years

thorium-230 α 75 000 years

thorium-233 β 22.3 minutes

(i) Mark with a cross ( ) the correct symbol to complete the following sentence.

α

The type of radiation which should be used is β

γ(1)

(ii) Name the source listed in the table that is most suitable for Sohanna’s treatment.

Give your reasoning.

most suitable source ...............................................................................................

reason ......................................................................................................................

................................................................................................................................(2) Q5

(Total 8 marks)

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6. (a) (i) What is meant by the term fundamental particle?

................................................................................................................................

................................................................................................................................(1)

(ii) Other than quarks, name another fundamental particle.

................................................................................................................................(1)

(b) The table gives the symbols and the charges for up and down quarks.

name symbol charge (e)

up quark u +23

down quark d − 13

(i) A proton consists of two up quarks and one down quark. Show that this accounts for the charge carried by a proton.

................................................................................................................................

................................................................................................................................(2)

(ii) Describe the structure of a neutron in terms of up and down quarks.

................................................................................................................................

................................................................................................................................(1)

(c) In β– decay, a neutron becomes a proton and an electron.

(i) Explain, in terms of quarks, what happens when a neutron becomes a proton.

................................................................................................................................(1)

(ii) What then happens to the electron?

................................................................................................................................(1) Q6

(Total 7 marks)

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7. (a) Fluorine-18 is a radioactive nuclide used in PET scans. It is made by bombarding oxygen-18 nuclei with protons. The equation for this reaction is

188O + 1

1p = 189F + X

Identify the other product, X, in this reaction.

.......................................................................................................................................(1)

(b) Fluorine-18 decays by emitting positrons.

(i) What is a positron?

................................................................................................................................

................................................................................................................................(2)

(ii) Fluorine-18 has a half-life of 110 minutes. Describe one advantage and one disadvantage of using a radioactive tracer with

a short half-life.

advantage ...............................................................................................................

................................................................................................................................(1)

disadvantage ..........................................................................................................

................................................................................................................................(1)

Question 7 continues overleaf

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(c) The detectors in a PET scanner are designed to detect gamma rays. The arrangement used is shown in the diagram.

The two gamma rays are produced by the annihilation of a positron and an electron. Where does the gamma ray energy come from?

.......................................................................................................................................

.......................................................................................................................................(2) Q7

(Total 7 marks)

radiation detector

gamma ray

gamma ray

radiation detector

positron electron

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8. Phillip noticed that the tyre became harder as he pumped more air into it.

(a) (i) Explain how the air in the tyre produces a pressure.

................................................................................................................................

................................................................................................................................(2)

(ii) Suggest why the pressure increases when more air is put in.

................................................................................................................................

................................................................................................................................(1)

(b) When Phillip had finished pumping up the tyre, the pressure of the air in it was1.70 × 105 Pa.

During a long journey, the temperature of the air in the tyre increases from 18°C to 22°C.

Calculate the new pressure of the air in the tyre, assuming the tyre volume did not change.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

...................... Pa(3) Q8

(Total 6 marks)

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9. The principle of pulse oximetry is based on the absorption characteristics of oxygenated and deoxygenated haemoglobin.

The pulse oximeter has two LEDs, one red (R) and one infrared (IR). These shine electromagnetic radiation at different wavelengths through a reasonably translucent site with good blood flow.

(a) The graph shows the absorption characteristics of oxygenated and deoxygenated haemoglobin.

(i) What does LED stand for?

................................................................................................................................(1)

(ii) Use the graph to estimate the two wavelengths used.

red light ..................................................................................................................

infrared light ..........................................................................................................(2)

(iii) Compare the absorption of the two wavelengths by oxygenated and deoxygenated haemoglobin.

................................................................................................................................

................................................................................................................................

................................................................................................................................(2)

absorption oflight

red infrared

600 700 800 900 1000

wavelength in 10�9 m (nm)

oxygenated haemoglobin

deoxygenated haemoglobin

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(b) The diagram shows the LEDs clipped onto a patient’s finger. A photodetector measures the amount of light that passes through the finger.

A typical arrangement is shown below.

(i) Pulse oximetry is described as a non-invasive method. Explain what this means.

................................................................................................................................

................................................................................................................................(1)

(ii) Light is absorbed by the haemoglobin. State two other factors which affect the amount of light measured by the

photodetector.

1 .............................................................................................................................

2 .............................................................................................................................(2)

R IR

photodetector

finger

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(iii) The output from the photodetector is shown in the graph below.

Describe and explain the important features of the output.

................................................................................................................................

................................................................................................................................

................................................................................................................................(2)

TOTAL FOR PAPER: 60 MARKS

END

Q9

(Total 10 marks)

time

light output

not yet attachedattached to finger

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