CIE IGCSE Physics

Topic Questions

5.2 Radioactivity

11 mark

Radioactive materials are usually stored in containers lined with metal. This is done to reduce the amount of radiation being emitted, to protect people nearby.

What type of metal is used for this purpose?

  • Lead

  • Aluminium

  • Steel

  • Copper

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21 mark

A student has three radioactive sources X, Y and Z. They devised the following experiment to determine what type of radiation each source is emitting. 

q2-easy-mcq-5-2-radioactivity-cie-igcse-physics

The student found that the radiation from X was stopped by a sheet of paper, Y was partially stopped by a few cm of lead and Z was stopped by a few mm of aluminium.

Which of the following correctly identifies each type of radiation

 

X

Y

Z

A

α-particle

β-particle

γ-ray

B

α-particle

γ-ray

β-particle

C

γ-ray

β-particle

α-particle

D

β-particle

γ-ray

α-particle

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31 mark

Which statement is not a method used to minimise the risk caused by working with radioactive sources.

  • Store the sources in lead-lined boxes.

  • Minimise the amount of time spent handling the sources.

  • Keep the source cold.

  • Keep the source as far away as possible, for example, using a pair of tongs.

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41 mark

Which statement about α-particles is correct?

  • α-particles consist of two protons and two electrons.

  • α-particles are the most penetrating type of radiation.

  • α-particles are a type of electromagnetic radiation.

  • α-particles are highly ionising.

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51 mark

There are three main types of radiation which may be emitted during radioactive decay: α-particles, β-particles and γ-rays.

Which of the following statements about these types of emissions is true?

  • α-particles are the only type of radiation to have a charge.

  •  γ-rays are stopped by a sheet of paper.

  • β-particles have the greatest ionising effect.

  • γ-rays are the most penetrating

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11 mark

Radioactive sources are often used in industry as part of manufacturing processes. The diagram below shows radiation being used to measure the thickness of a sheet of aluminium foil. The detector feeds back to the rollers to adjust the thickness.

q1-hard-mcq-5-2-radioactivity-cie-igcse-physics

What type of radiation would be the most suitable for this purpose?

  • α-particles

  • β-particles

  • γ-rays

  • All of the above.

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21 mark

The count rate of a radioactive material is measured using a detector. The reading on the detector is 88 counts per second. The background count rate is 40 counts per second.

The half-life of the radioactive substance is 12 hours. What is the reading on the detector after 24 hours?

  • 22

  • 12

  • 44

  • 52

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31 mark

A radioactive substance has a half-life of 4 days. 

It is currently emitting 8000 β-particles per minute.

How many β-particles will it emit per minute after 12 days?

  • 4000

  • 2000

  • 1000

  • 667

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41 mark

Beta and gamma radiation are passed through two charged metal plates as shown in the diagram below.

q4-hard-mcq-5-2-radioactivity-cie-igcse-physics

Which direction, if any, would the β-particles and γ-rays be deflected?

 

β-particles

γ-rays

A

into the page

continue straight

B

towards the negative plate

out of the page

C

continue straight

towards the negative plate

D

towards the positive plate

continue straight

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51 mark

Extended

 

The graph shows the activity of a radioactive source over a period of time.

5-2-5h-half-life-graph

What is the half-life of the source?

  • 5 seconds

  • 5 minutes

  • 300 seconds

  • 300 minutes

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11 mark

A student carried out an experiment to find the half-life of a radioactive substance. Their results are shown in the table below.

Time(seconds) Count-rate from source(counts per second)
0 300
20 200
40 150
60 100
80 75

What is the half -life of this substance?

  • 20 seconds

  • 40 seconds

  • 60 seconds

  • 80 seconds

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21 mark

Strontium-90 is a radioactive substance with the nuclide symbol S presubscript 38 presuperscript 90 r .

It decays by emitting radiation, as shown by the following equation.

S presubscript 38 presuperscript 90 r space rightwards arrow Y presubscript 39 presuperscript 90 space plus space ?

What is missing in this equation?

  • α-particle

  • Neutron

  • γ-ray

  • β-particle

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31 mark

A radioactive nucleus emits a β-particle.

What happens to the proton number and the nucleon number of this nucleus?

 

Proton number

Nucleon number

A

increases by 1

stays the same

B

stays the same

decreases by one

C

decreases by 2

decreases by 4

D

decreases by 1

stays the same

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41 mark

The count rate from a radioactive isotope is recorded every hour. The count rate is corrected for background radiation. The table shows the readings.

time / hours 0 1 2 3 4 5
corrected count rate / counts/s 1200 990 816 673 555 458

What estimate of the half-life of the isotope can be obtained from the readings in the table?

  • between 1 and 2 hours

  • between 2 and 3 hours

  • between 3 and 4 hours

  • between 4 and 5 hours

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51 mark

An nucleus of Uranium ( begin mathsize 24px style U presubscript 92 presuperscript 238 end style) is unstable and decays by emitting an α-particle. 

Which equation correctly describes this process?

  • U presubscript 92 presuperscript 238 rightwards arrow alpha presubscript 2 presuperscript 4 plus T presubscript 90 presuperscript 234 h

  • U presubscript 92 presuperscript 238 rightwards arrow alpha presubscript 2 presuperscript 4 plus U presubscript 90 presuperscript 234

  • U presubscript 92 presuperscript 238 plus alpha presubscript 2 presuperscript 4 rightwards arrow T presubscript 90 presuperscript 234 h

  • U presubscript 92 presuperscript 238 rightwards arrow alpha presubscript 2 presuperscript 4 plus R presubscript 88 presuperscript 234 a

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