P6

Question 1

what is the nucleus comprised of

Answer 1

protons and neutrons

Question 2

what is the relative charge of a proton, neutron, and electron

Answer 2

proton: +1
neutron: 0
electron: -1

Question 3

what is the proton number

Answer 3

the number of protons in the nucleus of an atom

Question 4

what is the nucleon number

Answer 4

the total number of protons and neutrons present in the nucleus of an atom

Question 5

how do you calculate the number of neutrons in an atom

Answer 5

nucleon number - proton number

Question 6

what is an isotope

Answer 6

atoms with the same number of protons but different number of neutrons

Question 7

what is background radiation

Answer 7

the radiation that exists around us all the time

Question 8

what are some sources of background radiation

Answer 8

radon gas (in the air), rocks and buildings, food and drinks, cosmic rays

Question 9

what is ionising nuclear radiation

Answer 9

radiation that has enough energy to remove electrons from the orbit of an atom, causing that atom to become ionised

Question 10

what is radioactive decay

Answer 10

a change in an unstable nucleus that can result in the emission of α-particles, β-particles, or γ-rays (to lose energy). these changes are spontaneous and random

Question 11

what is the nature of α-particles

Answer 11

2 protons, 2 neutrons

Question 12

what is the nature of β-particles

Answer 12

high energy, high speed electrons

Question 13

what is the nature of γ-rays

Answer 13

extremely high energy photon

Question 14

what is the nuclide notation of α, β, γ

Answer 14

Question 15

what are the relative ionising abilities of α, β, γ emissions and why

Answer 15

α- most ionising (most massive, most charge)
β- medium ionising (middle mass, middle charge)
γ- least ionising (no mass, no charge)

Question 16

what are the relative penetrative abilities of α, β, γ emissions

Answer 16

α- least penetrating (as most ionising)
β- medium (medium ionising)
γ- most (least ionising)

Question 17

material required to stop each form of ionising radiation

Answer 17

α- paper
β- several mm of aluminium
γ- several cm of lead/metres of concrete

Question 18

what are some safety measures when handling ionising radiation

Answer 18

• limit exposure time
• shielding: place barrier in between you and radiation
• increase distance to reduce intensity

Question 19

what is the nuclear decay equation for alpha decay

Answer 19

Question 20

what is the nuclear decay equation for beta decay

Answer 20

Question 21

what is the nuclear decay equation for gamma decay

Answer 21

Question 22

what are some of the applications of ionising radiation

Answer 22

• household fire (smoke) alarms (α)
• irradiating food to kill bacteria (γ)
• sterilisation of equipment (γ)
• measuring and controlling thicknesses of materials (β, γ)
• diagnosis and treatment of cancer (γ)

Question 23

how is ionising radiation measured

Answer 23

using a Geiger-Müller (GM) tube connected to a counter

Question 24

what is count rate measured in

Answer 24

counts / second, counts / minute

Question 25

what is half-life

Answer 25

the time taken for the number of unstable nuclei of a particular isotope to halve

Question 26

what is nuclear fusion and where does it occur

Answer 26

when two nuclei join and energy is released. it occurs in the Sun’s core

Question 27

what is nuclear fission and where does it occur

Answer 27

when a nuclei split into daughter nuclei, releasing energy. it occurs in nuclear reactors