Background radiation

A teacher measured the background radiation in a laboratory.

Which sources of background radiation are natural and which are man-made?

Tick () one box in each row.

The teacher measured the radiation emitted by four different types of radioactive rock.

Figure 12 shows the equipment used.

Each radioactive rock was placed below the detector one at a time.

The radiation was recorded as the number of counts in 1 minute.

The experiment was repeated with different materials between each rock and the detector.

Table 2 shows the results.

Which radioactive rock emitted only alpha radiation?

Give a reason for your answer.

Tick () one box.

Which radioactive rock emitted only beta radiation?

Give a reason for your answer.

Tick () one box.

The teacher took safety precautions during the experiment.

Which precaution would prevent the teacher from becoming contaminated by the radioactive rocks?

Tick () one box.

What is the activity of each rock after one half-life?

Tick () one box.

How does the activity of a radioactive source affect the risk of harm from the source?

Tick () one box.

Some isotopes emit nuclear radiation.

Carbon-12 and carbon-14 are both isotopes of carbon.

Complete the sentences.

Choose answers from the box.

The nucleus of a carbon-12 atom and the nucleus of a carbon-14 atom have the

same number of.

The nucleus of a carbon-12 atom and the nucleus of a carbon-14 atom have a

different number of.

Different radioactive isotopes have different half-lives.

What does ‘half-life’ mean?

Tick (✓) one box.

Table 2 shows the half-life of some different isotopes of carbon.

Which isotope is the least stable?

Tick (✓) one box.

Workers in nuclear power stations must be aware of nuclear irradiation and radioactive contamination.

Draw one line from each term to an example of the term.

Why are workers required to walk across a sticky floor before leaving the nuclear power station?

Tick (✓) one box.

The places where people work and live contribute to the nuclear radiation they are exposed to.

Table 3 shows the mean daily dose of radiation caused by two different jobs.

Calculate the number of days a nuclear power station worker must work before receiving the same dose that an aeroplane pilot receives in one day.

The process of nuclear fission takes place in nuclear power stations.

The process of nuclear fusion takes place in the Sun.

Draw one line from each process to its fuel.

Some isotopes emit nuclear radiation.

Carbon-14 and carbon-12 are isotopes of carbon. Compare the structure of an atom of carbon-14 with the structure of an atom of carbon-12.

Carbon-14 is a radioactive isotope. Carbon-14 has a half-life of 5700 years. What does ‘a half-life of 5700 years’ mean?

Table 1 gives the half-life of some other radioactive isotopes.

A sample of fluorine-17 has an activity that is one quarter of its original activity. Calculate the age of the sample of fluorine-17.

All of the isotopes in Table 1 emit beta radiation. Explain which isotope would cause the biggest risk to a person’s health based only on the half-life of each isotope.

People who work in the nuclear power industry need to be aware of irradiation and contamination. Describe the difference between irradiation and contamination.

Give one health risk to a person working close to a source of nuclear radiation.

Workers in nuclear power stations are monitored to check the radiation they emit. A worker stands 1 cm away from a radiation detector. The amount of radiation the worker emits is recorded. Explain why the worker needs to stand close to the radiation detector.

Workers in the nuclear power industry are exposed to nuclear radiation. Pilots on aircraft are exposed to cosmic radiation from space. daily dose caused by working in a nuclear power station = 0.00050 mSv hourly dose from cosmic rays to a pilot while flying = 0.0030 mSv Calculate the number of days it takes for a nuclear power station worker to receive the same dose as a pilot flying for 24 hours.

Radioactive isotopes emit different types of nuclear radiation.

What does an alpha particle consist of?

Tick (✓) one box.

What is a beta particle?

Tick (✓) one box.

A krypton (Kr) nucleus decays into a rubidium (Rb) nucleus by emitting a beta particle.

What is the correct equation for this decay?

Tick (✓) one box.

Figure 5 shows an experiment to demonstrate how alpha, beta and gamma radiation penetrate different materials.

The experiment takes place in a vacuum.

Three different materials are used:

• a sheet of paper

• a 0.5 cm thick sheet of aluminium

a 10 cm block of lead.

Each material is placed one at a time between the radioactive source and the GM tube.

The GM tube and counter show whether the material has stopped the radiation.

Complete Table 1 to show how alpha, beta and gamma radiation penetrate the materials in Figure 5.

Use the words Yes and No.

Part of Table 1 has been completed for you.

Alpha, beta and gamma radiation have different ionising powers.

Draw one line from each radiation type to the correct ionising power.

Some sources of background radiation are natural and other sources are man-made.

Which of the following is a man-made source of background radiation?

Tick (✓) one box.

The average background radiation dose per year in the UK is 2.0 millisieverts.

A dental X-ray gives a patient a radiation dose of 0.005 millisieverts.

Calculate how many dental X-rays would be the same as the average background radiation dose per year.

Radioactive waste from nuclear power stations is a man-made source of background radiation.

Which of the following is also a man-made source of background radiation? Tick (✓) one box.

Nuclear power stations use the process of nuclear fission. Complete the sentences to describe the process of nuclear fission. Choose answers from the box.

Plutonium-239 is one type of radioactive waste from nuclear power stations. The following nuclear equation represents the decay of plutonium-239 (Pu-239). 239 235 4

How does the nuclear equation show that alpha radiation is emitted when plutonium-239 decays?

Tick (✓) one box.

Figure 8 shows how the activity of a sample of plutonium-239 varies with time.

How much time will it take for the activity of the sample of plutonium-239 to fall to half of its initial activity?

What is the half-life of plutonium-239?

The radioactive waste from a nuclear power station is buried underground. People are warned to stay away from places where radioactive waste is buried. Suggest one risk of going near the place where radioactive waste is buried.

Radioactive waste from nuclear power stations is a man-made source of background radiation.

Give one other man-made source of background radiation.

Nuclear power stations use the energy released by nuclear fission to generate electricity.

Give the name of one nuclear fuel.

Nuclear fission releases energy. Describe the process of nuclear fission inside a nuclear reactor.

A new type of power station is being developed that will generate electricity using nuclear fusion. Explain how the process of nuclear fusion leads to the release of energy.

Nuclear fusion power stations will produce radioactive waste. This waste will have a much shorter half-life than the radioactive waste from a nuclear fission power station. Explain the advantage of the radioactive waste having a shorter half-life.

A teacher used a Geiger-Muller tube and counter to measure the number of counts in 60 seconds for a radioactive rock.

The counter recorded 819 counts in 60 seconds. The background radiation count rate was 0.30 counts per second.

Calculate the count rate for the rock.

A householder is worried about the radiation emitted by the granite worktop in his kitchen.

1 kg of granite has an activity of 1250 Bq. The kitchen worktop has a mass of 180 kg.

Calculate the activity of the kitchen worktop in Bq.

The average total radiation dose per year in the UK is 2.0 millisieverts.

Table 2 shows the effects of radiation dose on the human body.

The average radiation dose from the granite worktop is 0.003 millisieverts per day.

Explain why the householder should not be concerned about his yearly radiation dose from the granite worktop.

One year is 365 days.

Bananas are a source of background radiation. Some people think that the unit of radiation dose should be changed from sieverts to Banana Equivalent Dose.

Suggest one reason why the Banana Equivalent Dose may help the public be more aware of radiation risks.

A teacher used a Geiger-Muller tube and counter to measure the number of counts in 60 seconds for a radioactive rock.

The counter recorded 819 counts in 60 seconds. The background radiation count rate was 0.30 counts per second.

Calculate the count rate for the rock.

A householder is worried about the radiation emitted by the granite worktop in his kitchen.

1 kg of granite has an activity of 1250 Bq. The kitchen worktop has a mass of 180 kg.

Calculate the activity of the kitchen worktop in Bq.

The average total radiation dose per year in the UK is 2.0 millisieverts.

Table 1 shows the effects of radiation dose on the human body.

The average radiation dose from the granite worktop is 0.003 millisieverts per day.

Explain why the householder should not be concerned about his yearly radiation dose from the granite worktop.

One year is 365 days.

Bananas are a source of background radiation. Some people think that the unit of radiation dose should be changed from sieverts to Banana Equivalent Dose.

Suggest one reason why the Banana Equivalent Dose may help the public be more aware of radiation risks.