Radioactive decay

Gamma radiation can be significantly reduced by...

• Paper

• Aluminum

• Lead

What form of radiation is emitted by nuclei with too many neutrons?

• Alpha

• Gamma

• Beta

Gamma radiation is...

• An electromagnetic wave

• A helium nucleus

• An electron

Which form of radiation has the highest ionising power?

• Gamma

• Alpha

• Beta

What causes an atom's nucleus to become unstable?

• Too many or too few neutrons in the nucleus

• More electrons than protons

• Fewer electrons than protons

Uranium 238 emits an alpha particle to become what nucleus?

• Thorium-234

• Thorium-239

• Thorium-236

An alpha particle is...

• An electron

• A helium nucleus

• An electromagnetic wave

Which type of radiation can reach the furthest?

• Beta

• Gamma

• Alpha

What fraction of a radioisotope has decayed after two half-lives?

• One quarter

• All of it

• Three quarters