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GCSE Questions: Radioactivity

Q18.

(a) Atoms of different elements have different properties.

(i) Tick to indicate which of the following is the same for all atoms of the same element:

Atomic number
Mass number
  
Neutron number
  

[1 mark]

(ii) Tick to indicate which of the following is different for isotopes of the same element.

Number of electrons
  
Number of neutrons
Number of protons
  

 

[1 mark]

(b) A radioactive nucleus emits nuclear radiation.

(i) The graph below shows how the mass number and the atomic number change when nucleus D decays.

What type of radiation is emitted when nucleus D decays? Alpha particle radiation

[1 mark]

(ii) The graph below shows how the mass number and the atomic number change when nucleus E decays.

What type of radiation is emitted when nucleus E decays? Beta partcle radiation

[1 mark]

(c) Beta radiation can be used to monitor the thickness of paper during production. The diagram below shows the equipment used to do this.

The computer uses information from the radiation detector to change the size of the gap between the rollers.

Fill in the blanks in the following explanation of how the thickness of the paper is controlled by this equipment:

When the thickness of the paper between the beta source and the detector increases, the reading on the detector will decrease . This is because the amount of radiation absorbed by the paper will increase . The computer can then send instructions to the rollers to squeeze the paper more tightly.

[2 marks]

(d) All radioactive elements have a half-life.

(i) Tick the correct explanation of what is meant by the term ‘half-life’?

The time it takes for all the nuclei in a radioactive sample to split in half.  
The time it takes for the count rate of a radioactive sample to halve.
The time it takes for the radiation to travel half of its range in air.  
The time it takes for the sample to halve in mass.  

 

[1 mark]

(ii) Tick the correct explanation of why the radiation source used in part c should have a long half-life.

So the activity of the source is approximately constant.
So the amount of radiation decreases quickly.  
So the radiation has a long range in air.  
So the source is safe to use  

[1 mark]

(Total 8 marks)