Radiation - Definitions

Question 1

alpha particle

Answer 1

a helium nucleus. (ejected from an unstable nucleus)

Question 2

beta particle

Answer 2

a fast moving electron (ejected from an unstable nucleus)

Question 3

gamma ray

Answer 3

a high frequency electromagnetic wave. (ejected from an unstable nucleus)

Question 4

Ionisation

Answer 4

the addition or removal of an electron from a neutral atom, leaving it charged

Question 5

activity

Answer 5

the number of nuclei that decay in one second

Question 6

half life

Answer 6

the time for the activity of a radioactive source to decrease by half

Question 7

radiation weighting factor

Answer 7

a measure of the biological effect of a radiation

Question 8

fission

Answer 8

the splitting of a heavy nucleus into 2 smaller pieces and 2 or 3 neutrons

Question 9

chain reaction

Answer 9

when neutrons released in fission cause additional fission reactions to occur (and the process repeats)

Question 10

fusion

Answer 10

the joining of two nuclei to form a new heavier nucleus