Radioactivity

Question 1

Define: radiation

Answer 1

the emission of energy either as wave or particle

Question 2

Define: background radiation

Answer 2

ionising radiation in our environment which can be natural or artificial

Question 3

Define: ionising radiation

Answer 3

has enough energy to ionise (remove an electron from an atom), which can change the chemical composition of the material

Question 4

Define: non-ionising radiation

Answer 4

has enough energy to excite molecules and atoms, causing them to vibrate faster

Question 5

List 3 sources of natural background radiation

Answer 5

Isotopes in rocks, plants and animals, cosmic rays

Question 6

List 3 sources of artificial background radiation

Answer 6

medical procedures, nuclear power or weapons, industrial sterilisation or gauging devices

Question 7

Define: isotope

Answer 7

Atoms of the same element with varying amounts of neutrons, leading to different atomic weights.

Question 8

Define: radioisotope

Answer 8

isotopes emitting radiation to achieve a more stable form

Question 9

Define: half-life

Answer 9

the amount of time it take for a radioisotope to decay in half

Question 10

List the types of nuclear decay

Answer 10

alpha (α), beta (β), gamma (γ)

Question 11

Describe alpha radiation

Answer 11

2 neutrons, 2 protons (equivalent to a helium nuclei)

Question 12

Describe beta radiation

Answer 12

1 electron

Question 13

Describe gamma radiation

Answer 13

electromagnetic particle

Question 14

Describe the penetration depth of alpha radiation

Answer 14

Stopped by paper or a few centimetres of air

Question 15

Describe the penetration depth of beta radiation

Answer 15

Stopped by a few millimetres of aluminium

Question 16

Describe the penetration depth of gamma radiation

Answer 16

Stopped by centimetres of lead or metres of concrete

Question 17

Describe the ionising energy of alpha radiation

Answer 17

Strongly ionising

Question 18

Describe the ionising energy of beta radiation

Answer 18

Weakly ionising

Question 19

Describe the ionising energy of gamma radiation

Answer 19

Very weakly ionising

Question 20

State the formula for the quantity of remaining radioactive substance

Answer 20

remaining atoms = original quantity * (1/2)^(time passed/half-life)