Uses of nuclear radiation

This question is about using radioactivity and nuclear energy.

Gamma ray irradiation of food kills harmful bacteria by using

Which part of a nuclear reactor is used to absorb neutrons?

The isotope fluorine-18 is used in PET scans, which help to detect cancers.

Figure 20 shows a radioactive decay curve for a sample of fluorine-18.

Use the graph to calculate the percentage of fluorine-18 remaining after 150 minutes.

percentage of fluorine-18 remaining after 150 minutes =_........

Fluorine-18 releases positrons.

Describe what happens when positrons meet electrons.

Figure 21 shows what happens during a fission chain reaction.

Explain what happens when one neutron interacts with one uranium nucleus.

In 2023, Finland produced 4.4 GW of power from nuclear power plants.

The UK produced 8.9 GW of power from nuclear power plants.

Calculate the ratio of nuclear power produced in Finland compared with the UK as

power production in Finland

Give your answer to 2 significant figures (2 s.f.).

This question is about using radioactivity and nuclear energy.

Gamma ray irradiation of food kills harmful bacteria by using

Which part of a nuclear reactor is used to absorb neutrons?

The isotope fluorine-18 is used in PET scans, which help to detect cancers.

Figure 7 shows a radioactive decay curve for a sample of fluorine-18.

Use the graph to calculate the percentage of fluorine-18 remaining after 150 minutes.

percentage of fluorine-18 remaining after 150 minutes =_........

Fluorine-18 releases positrons.

Describe what happens when positrons meet electrons.

Figure 8 shows what happens during a fission chain reaction.

Explain what happens when one neutron interacts with one uranium nucleus.

In 2023, Finland produced 4.4 GW of power from nuclear power plants.

The UK produced 8.9 GW of power from nuclear power plants.

Calculate the ratio of nuclear power produced in Finland compared with the UK as

power production in Finland

Give your answer to 2 significant figures (2 s.f.).

Radiation is used to treat tumours (cancer).

The source of the radiation can be inside or outside the human body.

Which of these has a radiation source that can be positioned inside the body to treat tumours?

Figure 22 shows a PET scanner used to detect cancerous tumours.

A radioactive isotope is injected into a patient.

The isotope is absorbed by the tumour.

The isotope emits positrons from the location of the tumour.

The ring of radiation detectors rotates around the person.

Explain how the scan can give the location of the tumour.

Explain why the radioactive isotope injected into the patient must be produced near to the place where it is to be used.

Radiotherapy can involve irradiation of patients.

Radioactive tracers can involve contamination of patients.

State two differences between irradiation and radioactive contamination.

Figure 23 shows the decay curves of two different isotopes, Q and P.

Use the graph in Figure 23 to determine the half-life of isotope P.

Suggest a reason why the sample of isotope Q could be more dangerous to humans than the sample of isotope P.

Radiation is used to treat tumours (cancer).

The source of the radiation can be inside or outside the human body.

Which of these has a radiation source that can be positioned inside the body to treat tumours?

Figure 5 shows a PET scanner used to detect cancerous tumours.

A radioactive isotope is injected into a patient.

The isotope is absorbed by the tumour.

The isotope emits positrons from the location of the tumour.

The ring of radiation detectors rotates around the person.

Explain how the scan can give the location of the tumour.

Explain why the radioactive isotope injected into the patient must be produced near to the place where it is to be used.

Radiotherapy can involve irradiation of patients.

Radioactive tracers can involve contamination of patients.

State two differences between irradiation and radioactive contamination.

Figure 6 shows the decay curves of two different isotopes, Q and P.

Use the graph in Figure 6 to determine the half-life of isotope P.

Suggest a reason why the sample of isotope Q could be more dangerous to humans than the sample of isotope P.

This question is about radioactivity and its uses.

Which of these radiations does not have a charge?

Which of these radiations is used in smoke detectors?

The diagram in Figure 13 shows a radioactive source used to check the thickness of paper.

Name the type of radiation used to check the thickness of the paper.

Give the name of one device which could detect this type of radiation.

When the paper is the correct thickness, the count rate is 4000 counts per minute.

The count rate increases when the paper gets thinner.

Give one reason for this increase.

The rollers need to be adjusted if the count rate increases by 5%.

Calculate the maximum count rate that would be allowed before the rollers need to be adjusted.

maximum count rate =_........ counts per minute

*(d) Radioactivity from radioactive sources can be used in the diagnosis and treatment of cancer.

Describe one way radioactivity can be used in the diagnosis of cancer and one way radioactivity can be used in the treatment of cancer.

Radioactive tracers can be used when scanning a person’s kidneys.

A radioactive isotope is injected into a person’s blood stream.

The isotope emits radiation.

As the blood flows through the kidneys, this radiation is detected outside the body by a scanner.

What type of radiation travels from the kidney to the scanner?

During the scan, a technician needs to take readings for about 30 minutes.

The half‑life of the isotope used is about 6 hours.

1. State why an isotope with a half‑life of about 6 minutes is not suitable.

2. State why an isotope with a half‑life of about 6 days is not suitable.

State two ways of reducing the radiation risks to the technician.

Figure 17 is a diagram of a nuclear reactor.

Explain how pushing the control rods further into the reactor slows down the nuclear chain reaction.

The moderator in a nuclear reactor slows down the neutrons so that the neutrons are more likely to start other fission reactions.

In a nuclear reactor,

• the average speed of the fast neutrons is 3.010⁷m/s

• the average speed of the slow neutrons is 4.010³m/s

Calculate the average speed of the slow neutrons as a percentage of the average speed of the fast neutrons.

The nuclear reaction is the first stage in the process of generating electricity.

Describe how energy is transferred from the nuclear reaction to the next stage in the process.

Equations

Radioactive tracers can be used when scanning a person’s kidneys.

A radioactive isotope is injected into a person’s blood stream.

The isotope emits radiation.

As the blood flows through the kidneys, this radiation is detected outside the body by a scanner.

What type of radiation travels from the kidney to the scanner?

During the scan, a technician needs to take readings for about 30 minutes.

The half‑life of the isotope used is about 6 hours.

1. State why an isotope with a half‑life of about 6 minutes is not suitable.

2. State why an isotope with a half‑life of about 6 days is not suitable.

State two ways of reducing the radiation risks to the technician.

Figure 6 is a diagram of a nuclear reactor.

Explain how pushing the control rods further into the reactor slows down the nuclear chain reaction.

The moderator in a nuclear reactor slows down the neutrons so that the neutrons are more likely to start other fission reactions.

In a nuclear reactor,

• the average speed of the fast neutrons is 3.010⁷m/s

• the average speed of the slow neutrons is 4.010³m/s

Calculate the average speed of the slow neutrons as a percentage of the average speed of the fast neutrons.

The nuclear reaction is the first stage in the process of generating electricity.

Describe how energy is transferred from the nuclear reaction to the next stage in the process.

Sometimes food can become contaminated with radioactive substances.

Describe the harmful effects of eating food contaminated with radioactive substances.

Gamma radiation can be used in food processing to irradiate food.

Explain why some food is irradiated with gamma radiation.

Gamma radiation is part of the electromagnetic spectrum.

When the nucleus of an atom emits a gamma ray, the number of protons in the nucleus and the number of neutrons in the nucleus do not change.

State how the nucleus does change when it emits a gamma ray.

*(d) Gamma radiation is produced by radioactive decay.

Alpha radiation and beta radiation are also produced by radioactive decay.

Compare the processes of alpha decay and beta decay.

Your answer should include what each radiation is and what effect each decay has on the original nucleus.

Use words from the box to complete the sentences about nuclear fission of uranium‑235 (U‑235).

A neutron hits a nucleus of U‑235 and causes the nucleus to_........ .

Each fission releases energy, two daughter nuclei and some_........ .

In a nuclear reactor, one fission can set off a controlled_........ reaction.

Both U‑235 and oil can be used as energy sources for generating electricity.

1 kg of natural uranium can result in the generation of 45 000 units of electricity.

1 kg of oil can result in the generation of 5.0 units of electricity.

Calculate the mass of oil needed to generate the same amount of electricity as 1 kg of natural uranium.

mass of oil =_........

Both using nuclear fuel and burning oil produce harmful waste products.

State one harmful waste product from each process.

using nuclear fuel_........

*(d) Figure 14 shows a household smoke alarm that uses radioactivity to detect smoke.

The radioactive source in the smoke detector is americium–241.

The table in Figure 15 shows some information about americium–241 and two other radioactive sources.

Explain why americium‑241 is the best of these three sources to use in this smoke detector.

Use information from Figure 15 and your own knowledge about radiation.

Your answer should refer to

• properties of alpha and gamma radiation

• half‑life.

Energy from the nuclei of atoms can be used in medical diagnosis and treatment.

Fluorine‑18 is a radioactive isotope used in PET scanners for medical diagnosis.

Explain why fluorine‑18 must be produced close to the hospital where it is used.

Some tumours inside the body can be treated by using either alpha radiation or gamma radiation.

Explain why the source of alpha radiation is usually inside the body but the source of gamma radiation can be outside the body.

In a controlled chain reaction of uranium-235, which of these could cause a uranium-235 nucleus to undergo fission?

The kinetic energy of one of the particles released in a fission reaction is 1.210^–11J.

The mass of the particle is 1.410^–25kg.

Calculate the velocity of the particle.