Properties of electromagnetic waves 2 - AQA GCSE Physics Exam Questions

Practise 40 exam-style questions on Properties of electromagnetic waves 2 for AQA GCSE Physics. Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.

40 questions
1–6 marks each
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20 questions, marked as you go

Sample questions with model answers

Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.

Question 1

2 marks

X-rays and gamma rays can have the same wavelength.

Describe how X-rays and gamma rays differ in the way they are produced.

Model answer

Gamma rays come from changes in the nucleus of an atom, for example when a radioactive nucleus emits energy. X-rays are produced by electrons, outside the nucleus, for example when fast-moving electrons hit a metal target in an X-ray tube.

Explanation

Because the electromagnetic spectrum is continuous, X-rays and gamma rays overlap in wavelength. What distinguishes them is their origin: gamma rays come from the nucleus, X-rays from electrons.

Mark scheme

1 mark
gamma rays are produced by changes in the nucleus
allow emitted by unstable / radioactive nuclei
1 mark
X-rays are produced by changes involving electrons / outside the nucleus
allow X-rays are produced in an X-ray tube / by fast electrons hitting a metal target

Question 2

2 marks

A receptionist works next to an X-ray room. She receives an extra radiation dose of 0.02 mSv each week.

Calculate how many weeks it would take for her extra dose to reach 1 mSv.

Model answer

Number of weeks = 1 ÷ 0.02 = 50 weeks

Explanation

The dose builds up steadily, so the total dose = dose per week × number of weeks. Rearranging gives number of weeks = total dose ÷ dose per week. Because doses add up, small weekly doses can become significant over a year.

Mark scheme

1 mark
1 ÷ 0.02
an answer of 50 (weeks) scores 2 marks
1 mark
50 (weeks)

Question 3

3 marks

The dose from one chest X-ray is very small. Even so, doctors only send patients for X-rays when they are really needed.

Explain why.

Model answer

X-rays are ionising, so they can cause gene mutations and cancer. Every X-ray adds to the dose a person receives, and the risk of harm increases with the total dose. So an X-ray should only be taken when the benefit of finding out what is wrong is greater than the small extra risk.

Explanation

Radiation dose is a measure of the risk of harm, and even a small dose carries a small risk. Doctors weigh this risk against the benefit of a correct diagnosis, which is why unnecessary X-rays are avoided.

Mark scheme

1 mark
X-rays are ionising and can cause mutation of genes / cancer
1 mark
every exposure increases the risk / doses add up over time
allow there is no completely safe dose
1 mark
the benefit (diagnosis) must outweigh the risk

Question 4

4 marks

Scientists estimate that the risk of developing cancer from radiation is about 5% for each sievert of dose received.

A group of 10 000 people each receive a dose of 10 mSv from medical scans.
1000 mSv = 1 Sv

Estimate how many extra cases of cancer this could cause in the group.

Model answer

Dose for each person = 10 mSv = 0.01 Sv
Risk for each person = 5% × 0.01 = 0.05 × 0.01 = 0.0005
Extra cases = 0.0005 × 10 000 = 5

Explanation

Because radiation dose is a measure of risk, the risk is proportional to the dose: 5% per sievert means 0.05% for 0.01 Sv. Multiplying by the number of people gives the expected number of extra cases. It is an estimate: we cannot say which people will be affected.

Mark scheme

1 mark
10 mSv = 0.01 Sv
an answer of 5 scores 4 marks
1 mark
risk for each person = 0.05 × 0.01 = 0.0005
allow 5 × 10⁻⁴ or 0.05%; allow ecf from an incorrect conversion
1 mark
number of extra cases = 0.0005 × 10 000
allow total dose = 10 000 × 0.01 = 100 Sv, then 5% of 100
1 mark
5
allow ecf

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