4: Atoms and Radiation

Question 1

What is radioactive decay?

Answer 1

Some atomic nuclei are unstable. The nucleus gives out radiation as it changes to become more stable. This is a random process called radioactive decay.

Question 2

What are the four ways an atom may emit nuclear radiation?

Answer 2

• an alpha particle (α) - This consists of two neutrons and two protons, it is the same as a helium neucleus.
• a beta particle (β) - a high speed electron ejected from the nucleus as a neutron turns into a proton.
• a gamma ray (γ) - electromagnetic radiation from the nucleus.
• a neutron (n).

Question 3

What is half-life?

Answer 3

The half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve, or the time it takes for the count rate (or activity) from a sample containing the isotope to fall to half its initial level.

Question 4

What is radioactive contamination?

Answer 4

Radioactive contamination is the unwanted presence of materials containing radioactive atoms on other materials. The hazard from contamination is due to the decay of the contaminating atoms. The type of radiation affects the level of the hazard.

Question 5

What is irradiation?

Answer 5

Irradiation is the process of exposing an object to nuclear radiation. The irradiated object does not become radioactive.

Question 6

What is irradiation?

Answer 6

Irradiation is the process of exposing an object to nuclear radiation. The irradiated object does not become radioactive.