Atoms & Nuclear Radiation Practice Questions

What is meant by the activity of a radioactive source?

Give the unit of activity.

What is meant by the count-rate measured by the Geiger-Muller tube?

Complete the table to show what each type of nuclear radiation consists of.

Type of radiation	What the radiation consists of
alpha particle
beta particle
gamma ray

Describe the change that happens inside a nucleus when it emits a beta particle.

Which type of nuclear radiation is the most ionising?

What is meant by 'a half-life of 8 days'?

Radioactive decay is a random process. What is meant by 'random'?

A sample of iodine-131 has an activity of $6400$ Bq.

Calculate the activity of the sample after 24 days.

Give the values of $A$ and $Z$ in the nuclear equation.

A different nucleus emits a gamma ray. State the effect of this emission on the mass number and on the charge of the nucleus.

An unstable nucleus emits a single neutron. State the effect of this emission on the mass number and on the charge of the nucleus.

Give the values of $A$ and $Z$ in the nuclear equation.

Explain why the mass number of the nucleus does not change during beta decay.

Determine the half-life of the isotope.

Use the table.

Half-life = ________ minutes

Predict the count-rate from the sample at 50 minutes.

The student repeated the measurement at 10 minutes and obtained a count-rate of 312 counts per second.

Explain why this value is different from the value in the table.

State which type of nuclear radiation the source should emit.

Explain why the other two types of nuclear radiation would not be suitable for this use.

The count-rate at the detector increases.

What does this tell the factory about the sheet?

What is meant by irradiation?

A customer is worried that the strawberries will be radioactive when they are sold.

Explain why the customer is wrong.

What is meant by radioactive contamination?

Give one precaution that should be taken to protect the workers who operate the irradiation machine.

What is meant by peer review?

Explain why it is important that the findings of studies into the effects of radiation on humans are published and peer reviewed.

Show that the half-life of the source is 4.8 hours.

A different radioactive isotope has a half-life of 3 days.

Calculate the net decline in the activity of a sample of this isotope over 18 days.

Give your answer as a ratio.

Nucleus X decays by emitting an alpha particle.

Which point, A, B, C or D, represents the nucleus that is formed?

Explain your answer to part (a).

A different nucleus of the same isotope as X emits one alpha particle and then two beta particles.

Give the mass number and the atomic number of the final nucleus.

A technician in a research laboratory works with two radioactive materials.

• Source P is a gamma source completely sealed inside a metal capsule. It is kept in a lead-lined box and is taken out using long tongs.
• Source Q is a fine powder that emits alpha particles. A small amount of the powder was spilt on the bench and was not noticed for several hours.

Compare the hazards to the technician from irradiation by source P and from contamination by source Q.

In your answer you should also describe precautions that should be taken.

[6 marks]