P5 nuclear physics

Question 1

describe the composition of the nucleus

Answer 1

protons and neutrons

Question 2

relative charge of protons

Answer 2

+1

Question 3

relative charge of neutrons

Answer 3

0

Question 4

relative charge of electrons

Answer 4

-1

Question 5

define proton number

Answer 5

number of protons found in the nucleus

Question 6

define nucleon number

Answer 6

total number of protons and neutrons found in the nucleus

Question 7

relationship between proton number and relative charge on nucleus

Answer 7

proton number equal to relative charge of nucleus

Question 8

nuclide notation

Answer 8

A: proton number
Z: nucleon number

Question 9

describe the process of nuclear fission

Answer 9

• due to instability, heavy nuclei split apart
• into daughter nuclei
• energy released

Question 10

describe the process of nuclear fusion

Answer 10

• nuclei collide with high energy
• join to form larger nucleus
• energy released

Question 11

are some isotopes radioactive?

Answer 11

yes

Question 12

what is meant by ionising nuclear radiation

Answer 12

• carry enough energy to strip away electrons from atoms
• leave behind ions
• can be very harmful to living things and damage electronics

Question 13

what is meant by background radiation

Answer 13

• exists around us all the time

Question 14

significant sources of background radiation

Answer 14

• radon gas (in the air)
• rocks and buildings
• food and drink
• cosmic rays

Question 15

how can ionising nuclear radiation be measured

Answer 15

• using detector (geiger-müller tube)
• connected to a counter
• counts/s or counts/minute

Question 16

nature of alpha (α) emissions

Answer 16

• 2 protons
• 2 neutrons

Question 17

relative ionising effects of alpha emissions and why

Answer 17

• due to large mass and charge
• highly ionising

Question 18

relative penetrating abilities of alpha emissions

Answer 18

• least penetrating
• 5cm through air
• stopped by materials eg thin paper, skin

Question 19

nature of beta emissions

Answer 19

• high energy electron

Question 20

relative ionising effects of beta emissions

Answer 20

• lower charge of -1
• so only mildly ionising

Question 21

relative penetrating abilities of beta emissions

Answer 21

• can travel thru skin
• stopped by few mm of aluminium foil

Question 22

nature of gamma emissions

Answer 22

• EM waves
• high frequency
• high energy

Question 23

relative ionising effects of gamma emissions

Answer 23

• no mass, no charge
• weakly ionising

Question 24

relative penetrating abilities of gamma emissions

Answer 24

• most penetrating
• only be stopped by thick lead of concrete

Question 25

what is radioactive decay

Answer 25

- change in unstable nucleus - can result in emission of α-particles or β-particles and/or γ-radiation - changes are spontaneous and random

Question 26

in which radiation does nucleus change

Answer 26

α-decay or β-decay - changes to that of diff element

Question 27

change in nucleus that occurs during β-emission

Answer 27

Question 28

decay equation for emissions of α-particles

Answer 28

Question 29

decay equation for emission of β-particles

Answer 29

Question 30

decay equations for emission of γ-particles

Answer 30

Question 31

define half-life

Answer 31

- time taken for half the nuclei - of that isotope in any sample to decay

Question 32

applications of radioactivity

Answer 32

- household fire (smoke) alarms - irradiating food to kill bacteria - sterilisation of equipment using gamma rays - measuring and controlling thicknesses of materials - diagnosis and treatment of cancer using gamma rays

Question 33

effects of ionising nuclear radiation on living things

Answer 33

- cell death - mutations - cancer

Question 34

safety strategies for radioactivity

Answer 34

- limit exposure time to reduce experience of emissions - shielding. placing barrier between - increase distance from radioactive source, reduce intensity of radiation