The properties of alpha, beta and gamma radiation

Question 1

Define radiation

Answer 1

Where an unstable nucleus emits energy in the form of EM waves or subatomic particles to become more stable

Question 2

State the range, ionisation power and absorption material of alpha radiation

Answer 2

Range: 2-10cm
Ionisation power: High
Absorption material: paper

Question 3

State the range, ionisation power and absorption material of beta radiation

Answer 3

Range: 1m
Ionisation power: Weak
Absorption material: 3mm of aluminium foil

Question 4

State the range, ionisation power and absorption material of gamma radiation

Answer 4

Range: Infinite (inverse square law)
Ionisation power: Very weak
Absorption material: Several metres of concrete

Question 5

Which type of radiation is not deflected by electric and magnetic fields?

Answer 5

Gamma

Question 6

Describe an experiment which can be used to identify the type of radiation emitted from a source

Answer 6

1. Using a geiger-muller (GM) tube and counter, find the background count when the source
   is not present.
2. Place the source of radiation close to the GM tube and measure the count rate.
3. Place a sheet of paper between the source and GM tube and measure count rate again, if
   the count rate decreases significantly, then the source is emitting alpha radiation .
4. Repeat the above step using aluminium foil and several inches of lead . If there is a
   significant decrease in count rate for aluminium foil, then beta radiation is being emitted and
   if there is a significant decrease in count rate for the lead block, then gamma radiation is
   being emitted .

Question 7

Describe an experiment which can be used to show the inverse square law

Answer 7

1. Use a GM and counter to find the background count when the source is not present
2. Measure the count rate of the source at different distances from the GM tube
3. Plot a graph of corrected count rate against 1/x2, which will form a straight line

Question 8

In the production of aluminium foil what happens if less beta radiation is detected?

Answer 8

The rollers used to flatten the foil move closer together

Question 9

State 3 uses of gamma radiation

Answer 9

As a detector - can be dented using gamma cameras

Sterilise surgical equipment - kills bacteria

Radiation therapy - to kill cancerous cells

Production of steel sheets

Question 10

As gamma radiation moves through the air it…

Answer 10

spreads out in all directions equally

Question 11

State 2 precautions taken to safely handle radioactive sources

Answer 11

• Using long handled tongs to move the source
• Keeping source in a lead-lined container when not in use
• Keeping source as far away from yourself and others
• Never point source towards others

Question 12

Define background radiation

Answer 12

Radiation that is constantly in your surroundings from different sources

Question 13

Name 2 sources of background radiation

Answer 13

Radon gas
Artificial sources - nuclear weapons testing & meltdowns
Cosmic rays
Rocks - contain naturally occurring radioactive isotopes