edexcel gcse further additional science topic p3.2 x-rays and ecgs and p3.3 production, uses and...

TEST 4 – PART A

YEAR 5 TRIPLE SCIENCE PHYSICS 1 Turn over

Surname

Name

American Academy Larnaca

Year 5 Physics

Semester 2

Test 4

Unit P3

Applications of Physics

Topic 2 X-rays and ECG’s Topic 3 Radioactivity and its uses Friday 12 April 2013 Part A

Time: 20 minutes

• The total marks for this part is 20. • The total marks for the paper is 40. • The marks for each question are shown in square brackets.

Use this as a guide as to how much time to spend on each question. • Questions labelled with an asterisk (*) are ones where the quality of your written communication

will be assessed. You should take particular care with your spelling and grammar, as well as the clarity of expression, on these questions.

• Answer the questions in the spaces provided. There may be more space than you need.

TEST 4 – PART A


FORMULAE

You may find theses formulae useful

The relationship between focal length, object and image distance

current = number of particles per second × charge on each particle I = N × q

kinetic energy = electronic charge × accelerating potential difference

momentum = mass × velocity p = m × v

The relationship between temperature and volume for a gas

The relationship between volume and pressure for a gas V1 P1 = V2 P2

The relationship between the volume, pressure and temperature for a gas

r

Do not forget to include units in all your answers.

TEST 4 – PART A


_______________________________________________________________________________________ 1. Radioactivity is dangerous but also offers ways of treating various diseases. (a) Put a cross ( ) in the box next to the correct answer.

[1 mark] What is palliative care?

A A risky treatment that will cure the patient very quickly if successful

B Caring for the patient without treating the disease

C Treatment meant to reduce the effects of a disease without curing it completely

D Undergoing only one session of treatment

(b) Medical personnel working with radioactive sources has to follow safety rules when

handling such sources. Describe two such safety precautions used in hospitals.

[2 marks] . …………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… . …………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… (c) Technetium-99 (Tc-99) is a gamma source with a half-life of 6 hours.

It is used as a tracer in the diagnosis of brain cancer. Explain two properties that make Tc-99 suitable to use as a tracer.

[2 marks] . …………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… . …………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………

[Total for Question 1 = 5 marks] _______________________________________________________________________________________

TEST 4 – PART A


_______________________________________________________________________________________ 2. (a) Below you can see part of an electrocardiogram (ECG) of an adult.

(i) Put a cross ( ) in the box next to the answer.

[1 mark] Which row correctly describes the three different parts of the PQRST cycle?

P QRS T

A atria contract ventricles contract return to normal state

B ventricles contract atria contract return to normal state

C atria contract return to normal state ventricles contract

D ventricles contract return to normal state atria contract

(ii) Calculate the heartbeat (in beats per minute) for the ECG above.

[2 marks]

H b ………………………… b m (b) Marie has an ECG before and during exercise.

ECG before exercise ECG during exercise

Describe how these two ECGs show that Marie may have a problem during exercise.

You may add to the diagram if it helps your answer. [1 marks]

……………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………

Time (s)

P

Q

R

S

T

0.9 sec

TEST 4 – PART A


(c) Oximetry is another method used to monitor heart operation.

The graph shows the absorption characteristics of haemoglobin. Oxygenated haemoglobin absorbs more infrared radiation than red light. Deoxygenated haemoglobin absorbs more red light than infrared radiation.

(i) Identify which line, X or Y, represents oxygenated or deoxygenated haemoglobin.

[1 mark] Oxygenated haemoglobin: ………… Deoxygenated haemoglobin: ………… (ii) Below you can see a typical structure of an oximeter consisting of a photo-emitter

(an LED), that sends red and infrared radiation through the finger, and a photo-sensor that detects red and infrared radiation.

Oximeters can be used to detect hypoxia in a patient.

Hypoxia is a condition in which the body is deprived of adequate oxygen. Explain what frequencies will the photo-sensor primarily detect if a person suffers from hypoxia?

[2 marks] ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………


X

Y

absorption of light

wavelength (nm)

photo-emitter emits red and infrared

photo-detector

TEST 4 – PART A


_______________________________________________________________________________________ 3. Below you can see a diagram of an X-ray tube.

(a) The X-ray tube is switched on for 8 sec.

In this time interval 2.4 × 1018 electrons reach the anode. Calculate the current between the anode and the cathode. The charge of an electron is equal to e = 1.6 × 10–19 C.

[2 marks]

C ………………………… (b) The voltage between the cathode and anode accelerates the electrons.

The kinetic energy of an electron as it leaves the anode is 3.2 × 10–15J. Calculate the voltage needed to accelerate an electron from rest to this energy.

[2 marks]

V …………………………

anode

cathode

electrons

X-rays

TEST 4 – PART A

YEAR 5 TRIPLE SCIENCE PHYSICS 7

* (c) The release of electrons from the cathode is called thermionic emission.

The X-ray tube needs to contain a vacuum to increase the efficiency of X-ray production. Even so the collision of only about 1 in 100 electrons will produce an X-ray. Explain the above facts. Explain the term thermionic emission. Explain why the vacuum increases the efficiency of the X-ray tube. Explain the impact that the low efficiency of X-ray production has on the anode. Describe ways that are used to counter the impact.

[4 marks] ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………


TOTAL FOR PART A = 20 MARKS _______________________________________________________________________________________

END TOTAL FOR PAPER = 40 MARKS

TEST 4 – PART B


Surname

Name

American Academy Larnaca

Year 5 Physics

Semester 2

Test 4

Unit P3

Applications of Physics

Topic 2 X-rays and ECG’s Topic 3 Radioactivity and its uses Friday 12 April 2013 Part B

Time: 20 minutes

• The total marks for this part is 20. • The total marks for the paper is 40. • The marks for each question are shown in square brackets.

Use this as a guide as to how much time to spend on each question. • Questions labeled with an asterisk (*) are ones where the quality of your written communication

will be assessed. You should take particular care with your spelling and grammar, as well as the clarity of expression, on these questions.

• Answer the questions in the spaces provided. There may be more space than you need.

TEST 4 – PART B


FORMULAE

You may find theses formulae useful

The relationship between focal length, object and image distance

current = number of particles per second × charge on each particle I = N × q

kinetic energy = electronic charge × accelerating potential difference

momentum = mass × velocity p = m × v

The relationship between temperature and volume for a gas

The relationship between volume and pressure for a gas V1 P1 = V2 P2

The relationship between the volume, pressure and temperature for a gas

r

Do not forget to include units in all your answers.

TEST 4 – PART B


_______________________________________________________________________________________ 1. Scientists use many types of radiation.

Some types of radiations are particles, others are waves. (a) Draw one straight line from each of the following radiations to its description.

[3 marks]

radiation description

•

high frequency electromagnetic wave

gamma •

•

particles with the same mass as an electron and the same charge

neutron •

•

particles with the same mass as an electron but the opposite charge

positron •

•

particles with nearly the same mass as a proton but no charge

(b) (i) What is meant by the term fundamental particle?

[1 mark] ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… (ii) Put a cross ( ) in the box next to the correct answer.

[1 mark] Which of the following is a fundamental particle?

A A Hydrogen atom

B A Hydrogen nucleus, H

C A Hydrogen ion

D A Hydrogen electron

(iii) Compare the properties of an electron and a positron in terms of mass and charge.

[2 marks] ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………

TEST 4 – PART B


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

name symbol charge (e)

up quark u

down quark d

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

Explain your choice. [2 marks]

……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… (ii) Put a cross ( ) in the box next to the correct answer.

[1 mark] Which of the particles below would have a quark composition uud?

A A positron

B An electron

C A proton

D An antielectron

[Total for Question 1 = 10 marks]

_______________________________________________________________________________________

TEST 4 – PART B


_______________________________________________________________________________________ 2. The graph shows the number of neutrons plotted against the number of protons for the nuclei

of stable isotopes.

(a) Add letters to the graph to show the positions of unstable isotopes which emit the following

radiations. (i) Alpha particles – use a letter A

[1 mark] (ii) β– (beta-minus) particles – use a letter B

[1 mark] (iii) Positrons – use a letter P

[1 mark] (b) Sulphur-38 decays by emitting a beta-minus particle and a gamma ray to form an isotope

of chlorine. (i) W β− particle?

[1 mark] ………………………………………………………………………………………………………………………………………………………………………

TEST 4 – PART B


(ii) Complete the nuclear equation for this decay, by filling in all the boxes.

[2 marks]

* (iii) C m β− β+ emissions.

Explain what happens during these emissions to the nuclei and individual nucleons. Explain what happens to individual quarks during these emissions.

[4 marks] ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………………………………………………………


TOTAL FOR PART B = 20 MARKS _______________________________________________________________________________________

END TOTAL FOR PAPER = 40 MARKS

S Cl + β + γ 36

16

TEST 4 – MARK SCHEME – PART A


MARK SCHEME

PART A

p. 3 1. (a) C [1 mark] (b) Any two from [2 marks]

Large distance from source Shielding behind glass panes / Wearing special clothes / Using gloves (or similar) Containment of source (or similar) Minimising time spent near to source Dosimeter/film badge

(c) 1. Short half-life [1/2 mark] Limit exposure / Reduce danger (for patient / healthy tissues etc.) [1/2 mark] 2. Gamma emitter [1/2 mark] Least ionising / Most penetrating / Detected outside the body etc. [1/2 mark] p. 4 & 5 2. (a) (i) A [1 mark] (ii) f = 1 / T formula [1/2 mark]

f = 1 / 0.9 substitution [1/2 mark] f = 1.1 (Hz) calculation (ignore unit if wrong or absent) [1/2 mark] 1.1 × 60 = 66.7 = 67 (beats / min) conversion to min [1/2 mark] OR Ratio calculation 1 min = 60 sec time unit conversion [1/2 mark] 0.9 sec 1 beat 60 sec ? ratio [1/2 mark] 60 / 0.9 rearrangement [1/2 mark] = 67 calculation [1/2 mark]

(b) Any one from [1 mark]

The ST complex should be flat but in diagram B it is raised (Heart / Ventricles / Muscle) does not relax / recover (properly) (Problem) with depolarisation Mark given for identification, not explanation

(c) (i) Oxygenated: X Deoxygenated: Y [1 mark] (ii) Detect more IR / 910 nm compared to red / 660 nm [1 mark]

Hypoxia => more Deoxy-Hb [1/2 mark] Deoxy-Hb will absorb the red / 660 nm [1/2 mark]

TEST 4 – MARK SCHEME – PART A


p. 6 & 7 3. (a) N = 2.4 × 1018 / 8 = 3 × 1017 (e−s / sec) conversion to 1 sec [1/2 mark]

I = N e = 3 × 1017 × 1.6 × 10−19 formula &/V substitution [1/2 mark] I = 0.048 A calculation [1/2 mark] unit [1/2 mark]

(b) KE = e × V => 3.2 × 10−15 = 1.6 × 10−19 × V formula &/V substitution [1/2 mark]

V = 3.2 × 10−15 / 1.6 × 10−19 rearrangement [1/2 mark] V = 20 000 V calculation [1/2 mark] unit [1/2 mark]

* (c) Thermionic emission

− cathode is heated (or similar) to release e−s − Heat / Higher temperature provides extra energy for e−s to escape Necessity of vacuum − Vacuum does not slow down e−s − No collisions between e−s and air particles to stop them − More e−s reach anode => better efficiency Effect of low efficiency − 1% efficiency => 99% heat − produces anode wear − may melt anode due to high temperature Counteracting effects − anode of high melting point − rotating anode − cooling anode (with water)

Level Marks 1 1 – 2 Refers to at least 2 of the 4 points above

Describes at least one sub-point for each point 2 3 – 4 Refers to all 4 of the points above

Describes at least one sub-point for each point

TEST 4 – MARK SCHEME – PART B


MARK SCHEME

PART B

p. 3 & 4 1. (a) radiation description

•

high frequency electromagnetic wave

gamma •

•

particles with the same mass as an electron and the same charge

neutron •

•

particles with the same mass as an electron but the opposite charge

positron •

•

particles with nearly the same mass as a proton but no charge

Each correct line [1 mark] (b) (i) A particle not composed of other particles (or similar) [1 mark] (ii) D [1 mark] (iii) Same mass [1 mark]

Opposite charge (or similar) [1 mark] (c) (i) udd [1 mark]

Charge of n0 = 0 [1/2 mark] / − / − / 0 [1 mark] (if previous step missing)

(iii) C [1 mark]

TEST 4 – MARK SCHEME – PART B


p. 5 & 6 3. (a) (i)

(ii) (iii)

(b) (i) electron [1 mark] (ii)

C β

0 γ00

C β [1/2 mark] C γ [1/2 mark] C Α C [1/2 mark] Correct Z for Cl [1/2 mark]

* (iii) β− β+ e− released from nucleus e+ released from nucleus n0 p+ + e− p+ n0 + e− Z +1, N = const Z − , N = const d u + e− u d + e+ Accept answer as table Level Marks 1 1 − 2 Reference to release of e−s and e+s

Reference to changes in Z and N OR changes for n0 and p+ 2 3 − 4 Reference to changes in quarks

Connects changes in Z and N with changes in nucleons or quarks May write atomic and nucleon numbers over symbols May give charge calculation for n0 & p+ OR u & d transformations

(i) A, anywhere beyond Z = 82 [1 mark]

(ii) B, anywhere above belt [1 mark]

(iii) P, anywhere below belt [1 mark]

edexcel gcse further additional science topic p3.2 x-rays and ecgs and p3.3 production, uses and...

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