Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Fission and Fusion
47 practice questions
Topics covered
Practice questions
41–47 of 47
Question 41
5 marks · Normal
Answer and see the solution →Both fission and fusion reactions release energy. The conditions under which these reactions happen are very different.
(a)[2 marks]State one condition required for fission to occur, and one required for fusion.
(b)[2 marks]Explain why a chain reaction happens more readily with a large mass of uranium-235 than with a small mass.
(c)[1 mark]Suggest one reason why nuclear fusion reactors might be safer than fission reactors.
Question 42
5 marks · Normal
Answer and see the solution →The energy released in both fission and fusion reactions has important consequences for their use as energy sources.
(a)[3 marks]Explain how energy is released in the process of uranium-235 fission, mentioning both the particles produced and how energy is distributed among them.
(b)[2 marks]Describe one advantage and one disadvantage of using nuclear fusion, compared to nuclear fission, for providing electricity.
Question 43
5 marks · Normal
Answer and see the solution →The diagrams below show two types of nuclear reaction used to generate energy on Earth and in stars.
(a)[3 marks]Describe how energy is released in a nuclear fission reactor. Include the roles of the moderator and control rods in your answer.
(b)[2 marks]Explain why nuclear fusion reactions occur readily in stars but are harder to achieve on Earth.
Question 44
4 marks · Normal
Answer and see the solution →The nuclear reaction below shows a fusion reaction that occurs in stars:
(a)[2 marks]Explain what happens to the total mass of the products compared to the reactants in this reaction, and state what happens to the 'missing' mass.
(b)[2 marks]Describe one reason why nuclear fusion does not produce long-lived radioactive waste, unlike nuclear fission reactors.
Question 45
5 marks · Normal
Answer and see the solution →A nuclear power station can use either a fission reactor or, in the future, a fusion reactor.
(a)[3 marks]State two similarities and two differences between nuclear fission and nuclear fusion as sources of energy.
(b)[2 marks]Suggest one reason why fusion reactors could be more desirable than fission reactors for providing energy on Earth.
Question 46
5 marks · Hard
Answer and see the solution →Scientists want to develop fusion reactors as a future energy source, while fission reactors are already in use. The diagram represents a simplified nuclear reactor core.
A simple nuclear reactor core layout (a)[2 marks]Describe the function of: (i) the moderator (ii) the control rods in a nuclear fission reactor.
(b)[2 marks]Explain why a continuous chain reaction occurs in a fission reactor but not in a fusion reactor, even though both reactions can produce neutrons.
(c)[1 mark]Fusion occurs in stars. State two conditions required for fusion to occur and explain why these are necessary.
Question 47
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.