Three and four mark questions
These are similar to one and two mark questions but you will be expected to write in more depth for three and four mark questions.
Edexcel questions courtesy of Pearson Education Ltd.
Sample question 1 - Foundation and Higher
Question
In a nuclear reactor, a chain reaction is produced and controlled. Uranium-235 is the isotope used in many nuclear reactors.
Explain how the fission of uranium-235 can lead to a chain reaction. [4 marks]
As this is a four mark question, you should be looking to mention at least four different points.
For example:
The fission causes 2 or 3 neutrons to be released.
These neutrons can be absorbed by other nuclei.
This causes further uranium nuclei to fission.
This releases further neutrons that can be absorbed again, leading to a chain reaction.
Sample question 2 - Higher
Question
Explain what happens inside a nuclear reactor if neutron speeds are not controlled. [3 marks]
As this is a three mark question, you should be looking to mention at least three different points.
For example:
If the neutrons become too fast moving, the reaction will slow down.
This is because there are fewer fissions because:
Fission is more likely with slower neutrons.
Sample question 3 - Foundation and Higher
Question
Describe how the energy released in the chain reaction in a nuclear reactor is used to drive a turbine in a nuclear power station. [3 marks]
As this is a three mark question, you should be looking to mention at least three different points.
For example:
The reactor is surrounded by coolant.
Thermal energy from the chain reaction heats the coolant.
The hot coolant is used to turn water into steam, which is used to drive a turbine.