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Farr High School

NATIONAL 5 PHYSICS

Unit 2

Waves and Radiation

Exam Questions

(June 2017)

2

Wave Parameters and Behaviour

2011 Int2 12 MC

1. The following diagram gives information about a wave.

Which row shows the amplitude and wavelength of the wave? 1

Amplitude (m) Wavelength (m)

A 2 2

B 2 4

C 2 5

D 4 2

E 4 4

2010 Int2 13MC 2. The diagram gives information about a wave. The time taken for the waves to travel 108 m is 0·5 s. A student makes the following statements about the waves. I The wavelength of the waves is 27 m. II The amplitude of the waves is 20 m. III The frequency of the waves is 8 Hz. Which of the statements is/are correct? 1 A I only B II only C I and III only D II and III only E I, II and III

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2005 Int2 12MC 3. The diagram shows a transverse wave. The amplitude of the wave is A 2m B 3m C 4m D 6m E 8m 1

2011 Int2 12MC 4. The following diagram gives information about a wave. Which row shows the amplitude and wavelength of the wave?

National 5 Spec paper MC10

5. A satellite orbiting the Earth transmits television signals to a receiver. The signals take a time of 150 ms to reach the receiver. The distance between the satellite and the receiver is A 2∙0 × 106 m B 2∙25 × 107 m C 4∙5 × 107 m D 2∙0 × 109 m E 4∙5 × 1010 m. 1

Amplitude

(m) Wavelength

(m)

A 2 2

B 2 4

C 2 5

D 4 2

E 4 4

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National 5 Spec paper MC11 6. A wave machine in a swimming pool generates 15 waves per minute. The wavelength of these waves is 2∙0m. The frequency of the waves is

A 0∙25Hz B 0∙50Hz C 4∙0Hz D 15Hz E 30Hz. 1

National 5 2014 MC8

7. The period of vibration of a guitar string is 8 ms. The frequency of the sound produced by the guitar string is A 0·125 Hz B 12·5 Hz C 125 Hz D 800 Hz E 8000 Hz. 1

National 5 2015 MC7 8. The diagram represents a water wave.

The wavelength of the water wave is A 2 mm B 3 mm C 4 mm D 6 mm E 18 mm. 1

National 5 2016 MC8 9. A student makes the following statements about waves.

I Waves transfer energy. II A wave with a short wavelength diffracts more than a wave with a long wavelength. III The amplitude of a wave depends on its wavelength. Which of these statements is/are correct? 1

A I only B II only C III only D I and II only E I and III only

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National 5 2016 MC9 10. The diagram represents a wave.

The wavelength of the wave is the horizontal distance between points A P and Q B P and S C Q and R D R and S E S and T. 1

National 5 2016 MC10 11. The diagram represents the position of the crests of waves 3 seconds after a stone is

thrown into a pool of still water.

Which row in the table shows the speed and the frequency of the waves? 1

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2012 C 2b 12. A band is performing at music festival.

The festival is being broadcast live on radio. Drivers in two cars, A and B, are listening to the performance on the radio. The performance is being broadcast on two different wavebands, from the same transmitter. The radio in car A is tuned to an AM signal of frequency 1152 kHz. The radio in car B is tuned to an FM signal of frequency 102•5 MHz. Both cars drive into a valley surrounded by hills. The radio in car B loses the signal from the broadcast. Explain why this signal is lost. 2

2012 C 5 13. Bottlenose dolphins produce sounds in the frequency range 200 Hz – 150 kHz. Echolocation is the location of objects by using reflected sound. Bottlenose dolphins use ultrasounds for echolocation.

A sound of frequency 120 kHz is transmitted through the water by a bottlenose dolphin. (a) Using the data sheet, state the speed of sound waves in water. 1 (b) When the dolphin is 25 m from the sea wall, it emits a pulse of ultrasound. Calculate the time taken for this pulse to return to the dolphin. 4 (c) The dolphin changes the frequency of sound it produces to 100 kHz. (i) State the effect this will have on the time taken for the pulse to travel the 25 m. 1 (ii) Explain your answer. 1

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2013 C 2biv 14. In the aircraft industry non-destructive metal testing is used to look for flaws in aluminium propellers. Ultrasound pulses are sent at from a transmitter into the propeller being tested. If there are no flaws in the propeller the ultrasound will be reflected from the back edge of the propeller as shown at position A. The reflected signal is detected by a receiver. If a flaw is present inside the propeller a reflection from the flaw will take place inside the propeller as shown at position B.

The frequency of the ultrasound pulses is 15 MHz. Calculate the wavelength of the ultrasound pulses in the propeller. 3

2010 Int2 28 15. A satellite sends microwaves to a ground station on Earth. (a) The microwaves have a wavelength of 60mm. (i) Calculate the frequency of the waves. 3 (ii) Determine the period of the waves. 3 (b) The satellite sends radio waves along with the microwaves to the ground station. Will the radio waves be received by the ground station before, after or at the same time as the microwaves? Explain your answer. 2

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2005 Int2 29ab 16. The sun is 1.5 x 1011 m from Earth. The sun emits all radiations in the electromagnetic spectrum. All these radiations travel through space at 3 x 108 ms-1. (a) What do all waves transfer? 1 (b) Calculate the time taken for sunlight to reach Earth. 3

2007 C 1 17. A pupil is sent exam results by a text message on a mobile phone. The frequency of the signal received by the phone is 1900MHz. The mobile phone receives radio waves (signals). (a) What is the speed of radio waves? 1 (b) Calculate the wavelength of the signal. 3 (c) The pupil sends a video message from the mobile phone. The message is transmitted by microwaves. The message travels a total distance of 72 000 km. Calculate the time between the message being transmitted and received. 3

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2007 C 2b 18. The diagram shows how radio signals of different wavelengths are sent between a transmitter and a receiver. (a) Which of the waves in the diagram shows diffraction? 1 (b) What does this indicate about the wavelength of the diffracted wave compared to the other two waves? 1 (c) The Earth’s ionosphere is shown on the diagram. The ionosphere is a layer of charged particles in the upper atmosphere. High frequency waves are transmitted as sky waves. Explain how the transmitted waves reach the receiver. 1 (d) Super high frequency (SHF) signals are shown as space waves on the diagram. Although they can only travel in straight lines, they can be used for communications on Earth between a transmitter and receiver. Describe how the SHF signals get to the receiver. 2

2008 C 3a 19. In a sprint race at a school sports day, the runners start when they hear the sound of the starting pistol. An electronic timer is also started when the pistol is fired into the air. The runner in lane 1 is 3.2m from the starting pistol. The runner in lane 6 is 10 m From the starting pistol. The runner in lane 1 hears the starting pistol first. Calculate how much later the runner in lane 6 hears this sound after the runner in lane 1. 4

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2007 Int2 28 20. (a) Two types of waveform are shown.

(i) Which waveform represents a longitudinal wave? 1 (ii) Which waveform represents a sound wave? 1 (b) A signal generator is connected to a loudspeaker which produces a sound wave of frequency 2 kHz. (i) Calculate the wavelength of the sound wave in air. 3 (ii) The loudspeaker is placed a distance of 10.2m from a wall. Calculate the time taken for the sound to return to the loudspeaker. 3 (c) The loudspeaker is now placed in a tank of carbon dioxide gas. The frequency remains at 2 kHz. What effect does this have on the wavelength of the sound? Explain your answer. 2

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2009 C 2bc 21. A ship is carrying out a survey of the sea bed using ultrasound waves. When stationary, the ship transmits and receives pulses of ultrasound waves. The transmitted ultrasound waves have a frequency of 30 kHz. (a) What is the speed of ultrasound waves in water? 1 (b) One pulse of ultrasound is received back at the ship 0.36 s after being transmitted. Calculate the depth of the sea bed. 4

2009 Int2 29ab 22. Parking sensors are fitted to the rear bumper of some cars. A buzzer emits audible beeps, which become more frequent as the car moves closer to an object. Ultrasonic pulses are emitted from the rear of the car. Objects behind the car reflect the pulses, which are detected by sensors. Ultrasonic pulses travel at the speed of sound. (a) The time between these pulses being sent and received is 2 × 10–3 s . Calculate the distance between the object and the rear of the car. 4 (b) At a certain distance, the buzzer beeps every 0.125 s. Calculate the frequency of the beeps. 3

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National 5 Spec paper 6a 23. A water wave is diffracted when it passes through a gap in a barrier. The wavelength of

the wave is 10 mm. The gap is less than 10 mm.

Complete the diagram above to show the pattern of the wave to the right of the barrier.

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National 5 2014 4a 24. A student, fishing from a pier, counts four waves passing the end of the pier in

20 seconds. The student estimates that the wavelength of the waves is 12 m.

Calculate the speed of the water waves. 4

National 5 2016 4ci 25. An electromagnetic wave has a frequency of 1·2 GHz.

Show that the wavelength of this wave is 0·25 m. 2

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National 5 2015 3 26. A technician uses pulses of ultrasound (high frequency

sound) to detect imperfections in a sample of steel. The pulses of ultrasound are transmitted into the steel. The speed of ultrasound in steel is 5200 ms−1. Where there are no imperfections, the pulses of ultrasound travel through the steel and are reflected by the back wall of the steel. Where there are imperfections in the steel, the pulses of ultrasound are reflected by these imperfections. The reflected pulses return through the sample and are detected by the ultrasound receiver. The technician transmits pulses of ultrasound into the steel at positions X, Y and Z as shown.

The times between the pulses being transmitted and received for positions X and Y are shown in the graph.

(a) (i) State the time taken between the pulse being transmitted and received at position X. 1 (ii) Calculate the thickness of the steel sample at position X. 4 (b) On the graph, draw a line (in pencil) to show the reflected pulse from position Z. 2 (c) The ultrasound pulses used have a period of 4·0 μs. (i) Show that the frequency of the ultrasound pulses is 2·5 × 105 Hz. 2 (ii) Calculate the wavelength of the ultrasound pulses in the steel sample. 3 (d) The technician replaces the steel sample with a brass sample. The brass sample has the same thickness as the steel sample at position X. The technician transmits pulses of ultrasound into the brass at position P as shown. The time between the ultrasound pulse being transmitted and received at position P is greater than the time recorded at position X in the steel sample. State whether the speed of ultrasound in brass is less than, equal to or greater than the speed of ultrasound in steel. You must justify your answer. 2

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The Electromagnetic Spectrum

2013 Int2 MC 13 1. Which of the following electromagnetic waves has a higher frequency than microwaves and a lower frequency than visible light? A Gamma rays B Infrared C Radio D Ultraviolet E X-rays 1

2010 Int2 MC 14 2. The diagram shows members of the electromagnetic spectrum in order of increasing wavelength. Which row in the table identifies the radiations represented by the letters P, Q and R? 1

2007 Int2 17MC

3. A student makes the following statements about members of the electromagnetic spectrum. I Gamma rays have a longer wavelength than X-rays. II Ultraviolet rays have a longer wavelength than infrared rays. III TV and radio waves have a longer wavelength than microwaves. Which of the statements is/are correct? A I only B II only C III only D I and II only E II and III only 1

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2006 Int2 17MC 4. A student is asked to write down some types of electromagnetic waves in order of increasing wavelength. The student’s answer is not correct. Which two of these should be exchanged to make the student’s answer correct? 1 A X-rays and infrared B Visible light and infrared C Infrared and ultraviolet D Infrared and microwaves E X-rays and microwaves

National 5 Spec paper MC9 5. A student writes the following statements about electromagnetic waves.

I Electromagnetic waves all travel at the same speed in air. II Electromagnetic waves all have the same frequency. III Electromagnetic waves all transfer energy. Which of these statements is/are correct? A I only B II only C I and III only D II and III only E I, II and III

National 5 2015 MC9

6. A student makes the following statements about microwaves and radio waves. I In air, microwaves travel faster than radio waves. II In air, microwaves have a longer wavelength than radio waves. III Microwaves and radio waves are both members of the electromagnetic spectrum. Which of these statements is/are correct? A I only B III only C I and II only D I and III only E II and III only

National 5 2015 MC8

7. A student makes the following statements about different types of electromagnetic waves. I Light waves are transverse waves. II Radio waves travel at 340 m s−1 through air. III Ultraviolet waves have a longer wavelength than infrared waves. Which of these statements is/are correct? A I only B I and II only C I and III only D II and III only E I, II and III

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2012 C 4a 8. A toy helicopter is operated using an infrared signal from a remote control. The helicopter has a receiver that can detect infrared radiation.

State a suitable detector of infrared radiation. 1

2010 C 2a,bi 9. A hill lies between a radio and television transmitter and a house. The house is within the range of both the radio and television signals from the transmitter.

(a) In the house, a radio has good reception but a TV has poor reception from this transmitter. Suggest an explanation for this. 2 (b) State the speed of microwave signals in air. 1

2007 Int2 25a

10. A group of students visit a Laser Game Centre. The laser gun emits both a visible beam and an IR beam. Each target jacket contains three IR sensors. (a) What does the term IR stand for? 1 (b) Which of the two beams arrives at the target first? You must explain your answer. 2

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2013 C 14 11. Images from outer space can be obtained using space telescopes.

Two space telescopes which orbit the Earth are the Hubble space telescope and the Radioastron space telescope. (a) The telescopes detect radiations which are members of the electromagnetic spectrum. A diagram showing the electromagnetic spectrum is shown.

Gamma rays

P Q Visible light

Infra red Microwave Radio and TV

Electromagnetic Spectrum

Name radiations P and Q. 1 (b) The Hubble space telescope is nearing the end of its useful life and will be replaced with the James Webb space telescope. The James Webb space telescope is designed to detect infra-red radiation from outer space. Name a detector of infra-red radiation. 1

National 5 Spec paper 6b 12. The diagram below represents the electromagnetic spectrum.

(a) Identify radiation A. 1

(b) Apart from diffraction, state one property that all electromagnetic waves have in common. 1

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National 5 2014 5 13. The UV Index is an international standard measurement of the intensity of ultraviolet

radiation from the Sun. Its purpose is to help people to effectively protect themselves from UV rays. The UV index table is shown.

The UV index can be calculated using

The UV index is then rounded to the nearest whole number.

The tables below give information for elevation above sea level and cloud cover.

(a) At a particular location the total effect of UV radiation is 280. The elevation is 2 km above sea level with overcast skies. Calculate the UV index value for this location. 2

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13. (cont.)

(b) Applying sunscreen to the skin is one method of protecting people from the Sun’s harmful UV rays. UV radiation can be divided into three wavelength ranges, called UVA, UVB and UVC. A manufacturer carries out some tests on experimental sunscreens P, Q and R to determine how effective they are at absorbing UV radiation. The test results are displayed in the graph.

Using information from the graph, complete the following table. 1

(c) State one useful application of UV radiation. 1

National 5 2016 4ab 14. The diagram shows some parts of the electromagnetic spectrum in order of increasing wavelength.

(a) State a detector of infrared radiation. 1

(b) State which radiation in the electromagnetic spectrum has a wavelength shorter than X-rays. 1

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Light

2011 Int2 15 MC 1. The diagram shows a ray of light P incident on a rectangular glass block.

Which of the following are refracted rays? 1 A Q and R B R and S C S and T D Q and S E R and T

2008 Int2 15MC 2. A ray of light passes from air into a glass block as shown. Which row in the table shows the angle of incidence and the angle of refraction? 1

Angle of incidence Angle of refraction

A W Z

B W Y

C X Z

D X Y

E Z X

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2009 Int2 16MC 3. The diagram shows what happens to a ray of light when it strikes a glass block.

Which row in the table identifies the angle of incidence and the angle of refraction? 1

National 5 Spec paper MC 12 4. For a ray of light travelling from air into glass, which of the following statements

is/are correct? 1 I The speed of light always changes. II The speed of light sometimes changes. III The direction of light always changes. IV The direction of light sometimes changes.

A I only B III only C I and III only D I and IV only E II and IV

Angle of incidence Angle of refraction

A V W

B Y W

C Y X

D Z W

E Z X

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National 5 Spec paper MC 13 5. A ray of red light is incident on a glass block as shown.

Which row in the table shows the values of the angle of incidence and angle of refraction? 1

National 5 2016 MC 11 6. A ray of red light passes through a double glazed window. Which diagram shows the

path of the ray as it passes through the window? 1

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2012 Int2 27 7. Optical fibres are used to carry internet data using infra-red radiation. (a) State if the wavelength of infra-red radiation is greater than, the same as, or less than the wavelength of visible light. 1 (b) The diagram shows a view of an infra-red ray entering the end of a fibre.

(i) Copy and complete the diagram to show the path of the infra-red ray as it enters the glass from air. 1 (ii) Identify on your diagram the normal, the angle of incidence and the angle of refraction. 1

2005 Int2 30a 8. An osprey sees a fish in a loch. The diagram shows the path of a light ray from the fish to the osprey. (a) State the size of the angle of incidence. 1 (b) State the size of the angle of refraction. 1

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2006 Int2 29b 9. A student aims a laser beam at a triangular glass prism as shown. The beam changes direction at point X. Name the optical effect which occurs at point X. 1

2009 Int2 27c 10. Lasers can be used in optical fibres for medical purposes. (a) Copy and complete the path of the laser light along the optical fibre. 2 (b) Name the effect when the laser light hits the inside surface of the fibre. 1

National 5 2015 4b 11. When looking down into the calm water behind the pier the student sees a fish.

Sketch and complete the diagram to show the path of a ray of light from the fish to the student. You should include the normal in your diagram.

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National 5 2015 5abc 12. Diamonds are popular and sought after gemstones. Light is refracted as it enters and

leaves a diamond. The diagram shows a ray of light entering a diamond.

(a) Sketch the diagram and label the angle of incidence i and the angle of refraction r. 1

(b) State what happens to the speed of the light as it enters the diamond. 1

(c) The optical density of a gemstone is a measure of its ability to refract light. Gemstones of higher optical density cause more refraction. A ray of light is directed into a gemstone at an angle of incidence of 45º. The angle of refraction is then measured. This is repeated for different gemstones.

Diamond is known to have the highest optical density. Identify which gemstone is most likely to be diamond. 1

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National 5 2016 6 13. A student directs a ray of red light into a Perspex block to investigate refraction.

(a) Sketch the diagram and draw and label:

(i) the normal; 1

(ii) the angle of incidence i and the angle of refraction r. 1

(b) The student varies the angle of incidence and measures the corresponding angles of refraction. The results are plotted on a graph.

(i) Determine the angle of refraction when the angle of incidence is 12°. 1

(ii) Use the graph to predict the angle of refraction the student would obtain for an angle of incidence of 80°. 1

(c) Suggest why it would be good practice for the student to repeat the investigation a further three or four times. 1

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Nuclear Radiation 2011 Int2 17 MC

1. Activity and absorbed dose are quantities used in Dosimetry. Which row shows the unit of activity and the unit of absorbed dose? 1

Unit of activity Unit of absorbed dose

A gray becquerel

B becquerel sievert

C becquerel gray

D gray sievert

E sievert gray

2011 Int2 18 MC 2. The table shows the count rate of a radioactive source taken at regular time intervals. The count rate has been corrected for background radiation.

Time (minutes) 10 20 30 40 50

Count rate (counts per minute)

800 630 500 400 315

What is the half-life in minutes of the isotope? 1 A 10 B 15 C 20 D 30 E 40

2011 Int2 19 MC 3. In the following passage some words have been replaced by letters X and Y. In a nuclear reactor, fission is caused by X bombardment of a uranium nucleus. This causes the nucleus to split releasing neutrons and Y. Which row gives the words for X and Y? 1

X Y

A neutron energy

B proton energy

C electron protons

D neutron protons

E electron energy

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2012 Int2 18 MC 4. A student makes the following statements. I In an atom there are neutrons and electrons in the nucleus and protons which orbit the nucleus. II An alpha particle consists of two neutrons and two electrons. III A beta particle is a fast moving electron. Which of the statements is/are correct? 1 A I only B II only C III only D I and III only E I, II and III

2012 Int2 19 MC 5. A radioactive source emits alpha, beta and gamma radiation. A detector, connected to a counter, is placed 10 mm in front of the source. The counter records 400 counts per minute. A sheet of paper is placed between the source and the detector. The counter records 300 counts per minute. The radiation now detected is A alpha only B beta only C gamma only D alpha and beta only E beta and gamma only 1

2012 Int2 20 MC 6. A radioactive tracer is injected into a patient to study the flow of blood. The tracer should have a A short half-life and emit alpha particles B long half-life and emit beta particles C long half-life and emit gamma particles D long half-life and emit alpha particles E short half-life and emit gamma particles

2013 Int2 17 MC 7. A student makes the following statements. I The nucleus of an atom contains protons and electrons. II Gamma radiation produces the greatest ionisation density. III Beta particles are fast moving electrons. Which of the statements is/are correct? 1 A I only B II only C III only D I and III only E II and III only

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2013 Int2 19 MC 8. Which of the following describes the term ionisation?

A An atom losing an orbiting electron B An atom losing a proton C A nucleus emitting an alpha particle D A nucleus emitting a neutron E A nucleus emitting a gamma ray 1

2013 Int2 18 MC 9. A radioactive source emits α, β and γ radiation. Sheets of aluminium and paper are placed close to the source as shown.

Which row in the table shows the radiation(s) from the source detected at points X and Y? 1

Radiation(s) detected

at X Radiation detected at

Y

A α, γ γ

B β, γ α

C α β

D β γ

E γ γ

2013 Int2 20 MC 10. A student makes the following statements about radiation. I The half life of a radioactive source is half of the time it takes for its activity to reduce to zero. II The activity of a radioactive source is the number of decays per minute. III The risk of biological harm from radiation depends on the type of tissue exposed. Which of the statements is/are correct? 1 A I only B II only C III only D II and III only E I, II and III

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2010 Int2 17 MC 11. A student makes the following statements about a carbon atom. I The atom is made up only of protons and neutrons. II The nucleus of the atom contains protons, neutrons and electrons. III The nucleus of the atom contains only protons and neutrons. Which of the statements is/are correct? 1 A I only B II only C III only D I and II only E I and III only

2010 Int2 18 MC 12. Human tissue can be damaged by exposure to radiation. On which of the following factors does the risk of biological harm depend? 1 I The absorbed dose. II The type of radiation. III The body organs or tissue exposed. A I only B I and II only C II only D II and III only E I, II and III

2010 Int2 19 MC 13. Information about a radioactive source is given in Table 1. Table 1

Which row in Table 2 gives the correct information for the radioactive source? 1 Table 2

Activity Energy absorbed per

kilogram of tissue Radiation weighting

factor

500 MBq 0.2 μJ 10

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National 5 Spec paper MC14 14. A student writes the following statements about the activity of a radioactive source.

I The activity decreases with time. II The activity is measured in becquerels. III The activity is the number of decays per second.

Which of these statements is/are correct? A I only B II only C I and II only D II and III only E I, II and III

National 5 Spec paper MC15 15. A worker in a nuclear power station is exposed to 3∙0 mGy of gamma radiation and 0∙50 mGy of fast neutrons. The radiation weighting factor for gamma radiation is 1 and

for fast neutrons is 10. The total equivalent dose, in mSv, received by the worker is A 3·50 B 8·00 C 30·5 D 35·0 E 3 8·5. 1

National 5 2014 MC10

16. Which row describes alpha (α), beta (β) and gamma (γ) radiations? 1

National 5 2014 MC11 17. A sample of tissue is irradiated using a radioactive source. A student makes the following

statements about the sample. I The equivalent dose received by the sample is reduced by shielding the sample with a lead screen.

II The equivalent dose received by the sample is increased as the distance from the source to the sample is increased. III The equivalent dose received by the sample is increased by increasing the time of exposure of the sample to the radiation. Which of these statements is/are correct? 1 A I only B II only C I and II only D II and III only E I and III only

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National 5 2014 MC12 18. The half-life of a radioactive source is 64 years. In 2 hours, 1∙44 x 108 radioactive

nuclei in the source decay. What is the activity of the source in Bq? 1 A 2 x 104 B 4 x 104 C 1∙2 x 106 D 2∙25 x 106 E 7∙2 x 107

National 5 2014 MC13 19. A student makes the following statements about the fission process in a nuclear power

station. I Electrons are used to bombard a uranium nucleus. II Heat is produced. III The neutrons released can cause other nuclei to undergo fission. Which of these statements is/are correct? 1 A I only B II only C III only D I and II only E II and III only

National 5 2015 MC9 20. Alpha radiation ionises an atom. Which statement describes what happens to the atom?

A The atom splits in half. B The atom releases a neutron. C The atom becomes positively charged. D The atom gives out gamma radiation. E The atom releases heat. 1

National 5 2015 MC10 21. A sample of tissue is irradiated using a radioactive source. A student makes the following

statements. The equivalent dose received by the tissue is I reduced by shielding the tissue with a lead screen II increased as the distance from the source to the tissue is increased III increased by increasing the time of exposure of the tissue to the radiation. Which of the statements is/are correct? A I only B II only C I and II only D II and III only E I and III only

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National 5 2015 MC11 22. A sample of tissue receives an absorbed dose of 16 µGy from alpha particles. The

radiation weighting factor for alpha particles is 20. The equivalent dose received by the sample is A 0 ·80 µSv B 1·25 µSv C 4 µSv D 36 µSv E 320 µSv. 1

National 5 2015 MC12 23. For a particular radioactive source, 240 atoms decay in 1 minute. The activity of this

source is A 4 Bq B 180 Bq C 240 Bq D 300 Bq E 14 400 Bq. 1

National 5 2015 MC13 24. The letters X, Y and Z represent missing words from the following passage.

During a nuclear X reaction two nuclei of smaller mass number combine to produce a nucleus of larger mass number. During a nuclear Y reaction a nucleus of larger mass number splits into two nuclei of smaller mass number. Both of these reactions are important because these processes can release Z . Which row in the table shows the missing words? 1

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National 5 2016 MC12 25. Which row in the table shows how the mass and charge of an alpha particle compares

to the mass and charge of a beta particle? 1

National 5 2016 MC13 26. During ionisation an atom becomes a positive ion. Which of the following has been

removed from the atom? 1 A An alpha particle B An electron C A gamma ray D A neutron E A proton

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2011 C 6 27. A teacher is demonstrating absorption of alpha, beta and gamma radiations.

(a) The teacher explains that when these radiations are absorbed they may cause ionisation in the absorbing material.

(i) (A) State which of the two diagrams below represents an ionised atom. 1 (B) Explain your answer. 1

(ii) State which type of radiation: alpha, beta or gamma causes most

ionization. 1

(b) The radioactive sources are stored in lead-lined boxes. This is a safety precaution to minimise exposure of students and teacher to radiations from the sources. State one further safety precaution that should be taken by the teacher when handling the radioactive sources. 1

(c) Radioactive materials are used in hospitals.

(i) State one medical use of radiation where the radiation is used to

destroy cells. 1

(ii) A hospital physicist is working with some radioactive materials. The physicist wears a badge containing photographic film. Light cannot reach the film.

When developed, it is found that the film behind both the uncovered window and the window covered with 1 mm thick aluminium have turned black. State which type of radiation could cause the film in only these areas to turn black. 1

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2012 C 6 28. Aircraft welding joints must be checked regularly for cracks and other faults. A radioactive source can be used to carry out these checks.

The radiation detector monitors the amount of radiation passing through the section of the aircraft being checked. (a) Explain how a crack in the section of the aircraft would be detected. 1 (b) The aircraft has to be checked regularly. These checks take 24 hours to complete. The following radioactive sources are available. (i) State what is meant by the term half-life. 1 (ii) Explain which source would be most suitable for the purpose of detecting cracks in the aircraft. 3 (c) The lead shield is used as a safety precaution to prevent workers being exposed to a large dose of radiation. State one other safety precaution that is necessary when working with radioactive sources. 1 (d) A different radioactive source has a half life of 12 hours. The source has an initial activity of 128 MBq. Calculate its activity after 2 days. 3

Source Half-life Radiation Emitted

W 20 years alpha

X 15 hours beta

Y 30 years gamma

Z 3 hours gamma

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2012 Int2 29 29. A technician checks the count rate of a radioactive source. A graph of countrate against time for the source is shown. The count rate has been corrected for background radiation.

(a) Use the graph to determine the half-life of the source. 2 (b) State two factors which can affect the background radiation level. 2 (c) The source emits gamma rays. State what is meant by a gamma ray. 1

2012 Int2 30 30. An ageing nuclear power station is being dismantled.

During the dismantling process a worker comes into contact with an object that emits 24 000 alpha particles in five minutes. Calculate the activity of the object. 3

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2013 Int2 30c 31. In a medical procedure, a radioactive chemical is injected into a patient. The chemical is prepared by the technician from a source which has an activity of 320 MBq. The source has a half-life of 6 hours. Calculate the activity of the source 18 hours later 3

2013 Int2 31a 32. A student is researching information on nuclear reactors. The following diagram is found on a website. It illustrates a type of reaction that takes place in a reactor.

(a) Name the type of nuclear reaction is shown in the diagram. 1 (b) The labels have been omitted at positions P, Q, R and S on the diagram. State clearly what each of these labels should be. 2

2010 Int2 29 33. In 1908 Ernest Rutherford conducted a series of experiments involving

alpha particles. (a) State what is meant by an alpha particle. 1

(b) Alpha particles produce a greater ionisation density than beta particles or gamma rays. What is meant by the term ionisation? 1

(c) A radioactive source emits alpha particles and has a half-life of 2·5 hours.

The source has an initial activity of 4·8 kBq. Calculate the time taken for its activity to decrease to 300 Bq. 2 (d) Calculate the number of decays in the sample in two minutes, when the activity of the source is 1·2 kBq. 3 (e) Some sources emit alpha particles and are stored in lead cases despite the fact that alpha particles cannot penetrate paper. Suggest a possible reason for storing these sources using this method. 1

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National 5 Spec paper 7 34. Trees continually absorb carbon-14 when they are alive. When a tree dies the carbon-14

contained in its wood is not replaced. Carbon-14 is radioactive and decays by beta emission.

(a) Following the tree’s death, the activity of the carbon-14 within a 25 mg sample of its

wood changes as shown.

(i) Use the graph to determine the half-life of carbon-14. 2

(ii) Calculate the time taken for the activity of this sample of carbon-14 to fall to 6·5 Bq. 3

(iii) During an archaeological dig, a 125 mg sample of the same type of wood was obtained. The activity of this sample was 40 Bq. Estimate the age of this sample. 3

(b) Explain why this method could not be used to estimate the age of a tree that died 100 years ago. 1

National 5 Spec paper 8 35. A technician uses a radioactive source to investigate the

effect of gamma rays on biological tissue.

(a) State what is meant by the term gamma rays. 1

(b) The wavelength of a gamma ray is 6·0 × 10—13 m. Calculate the frequency of the gamma ray. 3

(c) In one experiment, a biological tissue sample of mass 0·10 kg receives an absorbed dose of 50 μGy. Calculate the energy absorbed by the tissue. 3

(d) The radioactive source must be stored in a lead-lined container. Explain why a lead-lined container should be used. 1

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National 5 2014 6 36. A technician carries out an experiment, using the apparatus shown, to determine the half-

life of a radioactive source.

(a) State what is meant by the term half-life. 1

(b) The technician displays the data obtained from the experiment in the graph below.

(i) Describe how the apparatus could be used to obtain the experimental

data required to produce this graph. 3

(ii) Use information from the graph to determine the half-life of the radioactive source. 1

(iii) Determine the corrected count rate after 40 minutes. 2

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National 5 2014 8 37. An airport worker passes suitcases through an X-ray machine.

(a) The worker has a mass of 80·0 kg and on a particular day absorbs 7·2 mJ of energy from the X-ray machine.

(i) Calculate the absorbed dose received by the worker. 3

(ii) Calculate the equivalent dose received by the worker. 3

(b) X-rays can cause ionisation. Explain what is meant by ionisation. 1

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National 5 2015 6 38. A paper mill uses a radioactive source in a system to monitor the thickness of paper.

Radiation passing through the paper is detected by the Geiger-Müller tube. The count rate

is displayed on the counter as shown. The radioactive source has a half-life that allows the system to run continuously.

(a) State what happens to the count rate if the thickness of the paper decreases. 1 (b) The following radioactive sources are available.

(i) State which radioactive source should be used. You must explain your answer. 3 (ii) State what is meant by the term half-life. 1 (iii) State what is meant by a gamma ray. 1 (c) The graph below shows how the activity of another radioactive source varies with time.

Determine the half-life of this radioactive source. 1

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National 5 2016 7 39. A spacecraft uses a radioisotope thermoelectric generator (RTG) as a power source.

The RTG transforms the heat released by the radioactive decay of plutonium–238 into electrical energy.

(a) In 15 minutes, 7·92 × 1018 nuclei of plutonium-238 decay. Calculate the activity of the plutonium-238. 3 (b) Each decay produces heat that is transformed into 4·49 × 10−14 J of electrical

energy. Determine the power output of the RTG. 2

(c) Plutonium-238 emits alpha radiation. Explain why a source that emits alpha radiation requires less shielding than a source that emits gamma radiation. 1

National 5 2016 8 40. During medical testing a beta source is used to irradiate a sample of tissue of mass 0·50 kg from a distance of 0·10 m. The sample absorbs 9·6 × 10−5 J of energy from the beta source.

(a) (i) Calculate the absorbed dose received by the sample. 3 (ii) Calculate the equivalent dose received by the sample. 3 (b) The beta source used during testing has a half-life of 36 hours. The initial activity of the beta source is 12 kBq. Determine the activity of the source 144 hours later. 3

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Various 2011 C 1

1. A mountain climber carries a device which receives radio signals from satellites to determine the climber’s position. The device can also be used to send the climber’s position to the emergency services in the event of an accident.

(a) One satellite sends a radio signal that is received by the device 0.068 s after transmission.

(i) State the speed of the radio signal. 1 (ii) Calculate the distance between this satellite and the climber. 3 (b) The device sends a radio signal to the emergency services.

The frequency of the signal is 2100 MHz. Calculate the wavelength of this signal. 3

2012 C 1b 2. In the summer of 2012 the Olympic Games were held in London. Television pictures of the Games were transmitted from London to Washington via a satellite. Television signals are transmitted using microwaves. The diagram shows the signals being transmitted from London to the satellite. This satellite transmited these signals to a ground station in Washington.

The frequency of the microwaves used for transmission was 12 GHz. (a) State the speed of microwaves. 1 (b) Calculate the wavelength of these microwaves. 3

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Open Ended Questions National5 2014 7

1. A fire engine on its way to an emergency is travelling along a main street. The siren on the fire engine is sounding. A student standing in a nearby street cannot see the fire engine but can hear the siren.

Use your knowledge of physics to comment on why the student can hear the siren even though the fire engine is not in view. 3

National5 2016 5 2. A Physics textbook contains the following statement.

“Electromagnetic waves can be sent out like ripples on a pond.” Using your knowledge of physics, comment on the similarities and/or differences between electromagnetic waves and the ripples on a pond. 3