GCSE Physics - Radioactivity

Question 1 [1 mark]

What type of radiation is stopped by a sheet of paper?

Answer: Alpha radiation

Accept:

• 'Alpha particles'
• 'Alpha'
• 'α radiation'

Do not accept: 'Alpha rays'

Question 2 [2 marks]

Complete the sentence: Radioactive decay is a ___ process where an unstable nucleus releases ___ to become more stable.

Answer: random, radiation

Award marks as follows:

• 1 mark for 'random'
• 1 mark for 'radiation'

Accept 'energy' for second gap

Question 3 [1 mark]

Unit for measuring activity

Answer: B) Becquerels

Accept: 'Bq' or 'Becquerel'

Question 4 [2 marks]

Two ways to protect from gamma radiation

Answer: Any two from:

• Use lead shielding/thick lead
• Increase distance from source
• Reduce exposure time
• Use concrete shielding

Award 1 mark for each correct method

Question 5 [2 marks]

Half-life calculation

Answer: 25g

Award marks as follows:

• 1 mark for identifying 2 half-lives have passed
• 1 mark for correct final answer of 25g

Working: 100g → 50g → 25g

Question 6 [2 marks]

Contamination definition and example

Answer:

• Definition (1 mark): When radioactive material gets onto or into something it shouldn't
• Example (1 mark): Any one from:
  • Radioactive dust on clothing
  • Radioactive material in food/water
  • Radioactive particles on skin

Question 7 [1 mark]

Greatest penetrating power

Answer: Gamma radiation

Accept: 'gamma', 'gamma rays', 'γ radiation'

Question 8 [2 marks]

Geiger counter explanation

Answer:

• 1 mark: Geiger counter detects radiation
• 1 mark: More radiation reaches detector when closer to source

Accept any clear explanation of increased detection rate with proximity

Question 9 [2 marks]

Uses of radioactivity in medicine

Answer: Any two from:

• Treating cancer/radiotherapy
• Taking X-rays/medical imaging
• Sterilizing medical equipment
• Diagnosing illness/medical tracers

1 mark for each correct use. Accept any clear medical application

Question 10 [1 mark]

Atomic number after alpha emission

Answer: Decreases by 2

Accept: 'reduces by 2', 'goes down by 2'