Radiation (Physics)

Question 1

What is Alpha

Answer 1

Alpha is a helium nucleus (made up of 2 protons and 2 neutron). It has a large mass.

Question 2

What is Beta

Answer 2

Beta is a fast moving electron. It has a negative charge. It has a very small mass.

Question 3

What is Gamma

Answer 3

Gamma is a high energy EM wave. These are caused by changes in the nucleus. They have no mass and no energy.

Question 4

What is ionisation

Answer 4

When a neutral atom becomes charged we say it has been ionised.

Question 5

How do each types of the radiation ionise.

Answer 5

Alpha - Highly ionising
Beta - Weakly ionising
Gamma - Weakly ionising

Question 6

What material can’t each of the radiations pass through

Answer 6

Alpha - Paper
Beta - Aluminium
Gamma - 3cm of Lead

Question 7

What is D?

Answer 7

Absorbed Dose (Gy)

How much energy is absorbed by 1kg of substance.

1 joule per kilogram = 1 gray.

Question 8

What is H?

Answer 8

Equivalent Dose (Sv)

How much energy is absorbed by 1kg of substance.
Radiation weighting factor is included.

Question 9

What is Wr

Answer 9

Radiation Weighting Factor

This tells us how much harm the radiation causes.

This is a measure of ionisation.

Question 10

What is E

Answer 10

Energy Absorbed (J)

Question 11

What is Activity?

Answer 11

How many decays per second.

1 decay per second = 1 becquerel.

Question 12

What is Dose Limit.

Answer 12

Average annual background radiation in the UK is 2.2mSv.

The annual effective dose limit for a member of the public is 1.5mSv.

The annual effective dose limit for a radiation worker is 20mSv.

Question 13

What is Half-life?

Answer 13

Half-life is the times it take for the activity (of a radioactive source) to halve. (Is the half-life of that source).

Question 14

What is Fission?

Answer 14

A larger nucleus splits and releases energy and neutrons.

These neutrons cause further fission reactions. This is a self sustaining reaction (chain reaction).

Question 15

What is fusion?

Answer 15

Fusion is when light nuclei join together to release energy.

This will be self sustaining when they get it to work with no net energy in.

Question 16

Name some sources of background radiation.

Answer 16

Radon Gas - This is released during radioactive decay of minerals in some rocks.

Cosmic Rays - Radioactivity from space.

Medical - Radioscopes and tracers.

Food - Lo salt, brazil nuts, bananas (high potassium foods).