P6.2 Uses And Hazards

Question 1

Radioactive contamination

Answer 1

Presence of unwanted radioactive nuclei on other materials

Question 2

Irradiation

Answer 2

Process of exposing a material to nuclear radiation
Material does not become radioactive

Question 3

Give 3 practical applications of radioactive materials.

Answer 3

Medical tracers
• Radiotherapy
• Smoke alarms

Question 4

What kind of radiation is used in smoke detectors

Answer 4

Alpha radiation

Question 5

How do smoke alarms work

Answer 5

Alpha radiation is emitted into the air, reaching a detector and completing the circuit. If smoke is present, it blocks alpha radiation so it does not reach the detector and the circuit is broken, causing an alarm to sound.

Question 6

Give a use of beta emitters

Answer 6

Thickness monitoring of paper.

Question 7

How does thickness monitoring work

Answer 7

A source and receiver are placed on either side of the sheet. If there is a drop or rise in the number of particles detected, the thickness has changed and needs adjusting.

Question 8

Why are isotopes with long half-lives particularly harmful

Answer 8

They remain radioactive for much longer periods of time.
They must be stored in specific ways to avoid humans and the environment from being exposed to radiation for too long.

Question 9

State two uses of nuclear radiation in the field of medicine

Answer 9

Examining of internal organs.
2. Controlling and destroying unwanted tissue.

Question 10

How is radiation used in sterilisation

Answer 10

Gamma emitters are used to kill bacteria/parasites on equipment

Question 11

What kind of radiation is used for radiotherapy

Answer 11

Gamma radiation

Question 12

Explain the process of chemotherapy

Answer 12

Gamma emitters direct gamma rays onto specific areas with cancerous cells.
• The cells absorb the radiation and die.

Question 13

What are the risks of ionising radiation to people

Answer 13

It can damage living cells, causing them to die or mutate and become cancerous

Question 14

What is nuclear fusion

Answer 14

The joining of two light nuclei to produce a heavier nuclei and release energy

Question 15

Name two isotopes of hydrogen which are commonly used in nuclear fusion

Answer 15

Deuterium and Tritium

Question 16

Which releases more energy, nuclear fission or nuclear fusion

Answer 16

Nuclear fusion

Question 17

Explain the difficulty of generating energy through nuclear fusion

Answer 17

Fusion requires very high temperatures which in itself requires large quantities of energy and also requires casing which can withstand them

Question 18

What can mass be converted into

Answer 18

Energy

Question 19

What is nuclear fission

Answer 19

The splitting of large, unstable nuclei to form smaller more stable nuclei (+the emission of spare neutrons)

Question 20

What usually needs to happen to induce fission

Answer 20

The unstable nuclei must absorb a neutron.
• Spontaneous fission (where no neutron absorption occurs) is rare.

Question 21

Alongside two smaller nuclei, what else is emitted in a fission reaction

Answer 21

Two or three neutrons
• Gamma rays
• Energy

Question 22

What takes place during a chain reaction in a nuclear reactor

Answer 22

An unstable nucleus absorbs a neutron.
• The nucleus undergoes fission and releases 2 or 3 further neutrons.
• These induce more fission, which results in a chain reaction.