P4 - Properties of Alpha, Beta and Gamma Radiation

What are the three main types of nuclear radiation?

Alpha particles, beta particles, and gamma rays

What is the range in air of alpha particles?

Around 5 cm

What is the range in air of beta particles?

Around 15 cm

What is the range in air of gamma rays?

Several metres

What material stops alpha particles?

A single sheet of paper

What material stops beta particles?

A few millimetres of aluminium

What material stops gamma rays?

Several centimetres of lead (or thick concrete)

What is ionisation?

The process where radiation knocks electrons off atoms to form ions

What is ionising power?

A measure of how easily radiation can ionise atoms

Which type of radiation is the most ionising?

Alpha particles

Why are alpha particles strongly ionising?

Because they are large and highly charged, so they collide easily with atoms

Which type of radiation is moderately ionising?

Beta particles

Which type of radiation is the least ionising?

Gamma rays

Why is gamma radiation weakly ionising?

Because it is a wave with no mass or charge, so it is less likely to interact with atoms

Which type of radiation is the least penetrating?

Alpha particles

Which type of radiation is the most penetrating?

Gamma rays

What is the order of radiation types from least to most penetrating?

Alpha < Beta < Gamma

What is the order of radiation types from most to least ionising?

Alpha > Beta > Gamma

Why can alpha particles be stopped by paper?

Because they are large and lose energy quickly as they collide with air particles

Why do beta particles penetrate further than alpha?

Because they are smaller and faster, so they collide less often with atoms

Why do gamma rays travel furthest in air?

Because they are electromagnetic waves and don't interact much with matter

Do all three types of radiation cause ionisation?

Yes, but to different extents