Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Radioactivity and Particles
123 practice questions
Topics covered
Practice questions
111–120 of 123
Question 111
7 marks · Hard
Answer and see the solution →Nuclear power stations rely on an understanding of both fission and fusion.
(a)[3 marks]Outline how a chain reaction is started and controlled in a fission reactor, and explain why this is necessary for safe operation.
(b)[3 marks]Explain why fusion is the main source of energy in stars but not in current nuclear power stations.
(c)[1 mark]Give one reason why some scientists prefer the idea of fusion over fission as a future energy source on Earth.
Question 112
1 mark · Easy
Answer and check →Which unit is used to measure the activity of a radioactive source?
- A.joule (J)
- B.becquerel (Bq)
- C.watt (W)
- D.newton (N)
Question 113
3 marks · Easy
Answer and see the solution →A student measures the count rate from a radioactive source using a Geiger-Müller tube. The background count is 20 counts per minute. With the source in place, the count is 65 counts per minute.
(a)[1 mark]Calculate the count rate due to the source alone.
(b)[1 mark]Which unit should be used to record the activity?
(c)[1 mark]Suggest one way to reduce your own exposure to this radiation during the experiment.
Question 114
2 marks · Easy
Answer and see the solution →State the unit used for measuring the activity of a radioactive source. Which SI prefix would you use for an activity of 2,700,000 Bq?
Question 115
4 marks · Easy
Answer and see the solution →A radioactive isotope is used in a tracing experiment in a factory. Its measured activity is 5000 Bq at 10:00 am.
(a)[1 mark]State the unit of activity for a radioactive source, and what it measures.
(b)[1 mark]If the activity falls to 1250 Bq by 1:00 pm, how many half-lives have passed?
(c)[1 mark]If the half-life of the isotope is 1 hour, what will its activity be at 4:00 pm?
(d)[1 mark]Explain why radioactive tracers used in industry should have short half-lives.
Question 116
4 marks · Easy
Answer and see the solution →A sample of a radioactive material gives off radiation. A student is asked to describe this sample and measure its activity. The student is told to report results using standard units.
(a)[1 mark]State the unit used to measure the activity of a radioactive sample.
(b)[1 mark]Explain in one clear sentence what is meant by the activity of a radioactive sample.
(c)[1 mark]Name one piece of equipment that can be used to detect ionising radiation from this sample.
(d)[1 mark]Describe what happens to the activity of the sample over time.
Question 117
5 marks · Normal
Answer and see the solution →A hospital uses a radioactive tracer to detect problems in a patient's kidneys. The tracer contains an isotope that decays by beta emission. The activity of a sample is measured as 3.0 kBq.
(a)[2 marks]State what is meant by the unit becquerel (Bq) and convert the sample's activity to becquerels.
(b)[2 marks]Explain why a beta emitter is often chosen for medical tracers rather than an alpha emitter.
(c)[1 mark]Describe one safety precaution that should be taken when using radioactive tracers in medicine.
Question 118
4 marks · Normal
Answer and see the solution →Read these two statements about radioactivity: Statement 1: The activity of a radioactive sample is measured in becquerels (Bq). Statement 2: Gamma radiation is more penetrating than alpha radiation.
(a)[1 mark]Explain what is meant by the unit 'becquerel' (Bq).
(b)[1 mark]Why is gamma radiation more dangerous than alpha radiation outside the body? Give a reason.
(c)[1 mark]A sample has an activity of 500 Bq. How many decays does this represent per second?
(d)[1 mark]State one common way to detect ionising radiation in a laboratory.
Question 119
4 marks · Normal
Answer and see the solution →A sample containing a radioactive isotope has an initial activity of 200 Bq. The half-life of the isotope is found to be 15 minutes.
(a)[2 marks]Calculate the activity of the sample after 30 minutes.
(b)[1 mark]State the unit for activity.
(c)[1 mark]Explain what is meant by the 'half-life' of a radioactive isotope.
Question 120
5 marks · Normal
Answer and see the solution →A hospital uses a radioactive isotope that emits gamma radiation to sterilise medical equipment and measure the thickness of plastic film. The table shows typical penetrating and ionising properties of the three main types of radiation.
Penetrating and Ionising Properties Radiation Penetrating Power Ionising Power Alpha Low (stopped by paper) High Beta Medium (stopped by aluminium) Medium Gamma Very high (stopped by thick lead) Low (a)[2 marks]Explain, using information from the table, why gamma radiation is suitable for both sterilising equipment and measuring the thickness of plastic film.
(b)[2 marks]The activity of the radioactive source is measured in a laboratory. A scientist records a value of 5000 Bq at the start. State what the unit becquerel measures and convert the recorded activity to kBq.
(c)[1 mark]Describe one safety precaution that workers should follow when handling radioactive sources.