Topic 4: Atomic and Nuclear Physics

Question 1

Mass of a proton neutron and electron

Answer 1

Proton
- Mass: 1
- Charge +1

Neutron
- Mass: 1
- Charge: 0

Electron
- Mass 1/1840
- Charge -1

Question 2

What is an Isotope of an element

Answer 2

Atoms which contain the same number of protons but different number of neutrons

Question 3

What is ionisation

Answer 3

The loss or gain of electrons from neutral atoms to form ions

Question 4

An atom is radioactive when

Answer 4

The nucleus is unstable

Question 5

The process of emitting radition is called

Answer 5

Radioactivity

Question 6

Random meaning

Answer 6

Impossible to predict when a particular nucleus will decay

Question 7

Spontaneous meaning

Answer 7

Cannot be controlled by physical factors

Question 8

What is radioactive decay

Answer 8

The disintegration of an unstable nucleus with the release of alpha, beta, gamma

Question 9

An alpha particle is

Answer 9

A helium nucleus

Question 10

When a nucleus decays by alpha emission

Answer 10

Mass number decreased by 4
Atomic number decreased by 2

Question 11

A beta particle

Answer 11

An electron ejected from the nucleus

Question 12

When a nucleus decays by beta emission

Answer 12

Its mass number stays the same
Atomic number increases by 1

Question 13

Gamma radiation is

Answer 13

A wave of electromagnetic energy

Question 14

When a gamma ray is emitted from an element

Answer 14

Neither the mass number nor the atomic number change

Question 15

What is background radiation

Answer 15

The radioactivity that is detected when there are no known radioactive sources present

Question 16

Sources of background radiation

Answer 16

Radioactive rocks beneath the ground
Cosmic Rays
Nuclear Medicine
Waste from nuclear power stations

Question 17

Safety when using radioactive sources

Answer 17

Maximise resistance - use tongs
Minimise Exposure Time
Shielding - Store in Led
Wear protective clothing

Question 18

The activity of a radioactive source is

Answer 18

The number of nuclei which decay per second

Question 19

The unit of activity is

Answer 19

Becquerel

Question 20

Half life is

Answer 20

The time taken for the activity to fall to 50% of its original value

Question 21

The half life of radon gas is 4 days what does this mean

Answer 21

The activity will half every 4 days

Question 22

Uses of radioactivity in medicine

Answer 22

Sterilisation of surgical instruments

Gamma rays can pass through medical equipment

Question 23

Uses of radioactivity in radiotherapy

Answer 23

High does can be directed at cancerous cells to kill them

Question 24

Uses of radioactivity from outside the body

Answer 24

Using X-rays or gamma rays from radioactive cobalt

Question 25

Uses of radioactivity from inside the body

Answer 25

putting radioactive materials into the tumour or close to it

Question 26

What source can be used to check for leaks in a water pipe

Answer 26

Gamma source has short half life and several days to allow emission to build up in soil but not too long that exposure is limited

Question 27

What can be used for Smoke detectors

Answer 27

Alpha as it is absorbed by a few cm of air

Question 28

What can be used in agriculture

Answer 28

Gamma radiation can be used to kill bacteria on fresh food

Question 29

Nuclear fission is

Answer 29

The splitting of a large unstable nucleus into smaller lighter more stable nuclei with the release of energy

Question 30

Outline the process of nuclear fission

Answer 30

A neutron is absorbed by U-235
This forms U-236
U 236 is unstable so it splits
Smaller lighter nuclei form
2 or 3 fission neutrons are also produced
as some of the mass is gone it turns to energy

Question 31

Advantages of nuclear fission for energy

Answer 31

• Advantages
  You get 1 million times more energy than fossil fuels
  Well paid employment

Disadvantages
- Non Renewable uranium is limited
Long lived radioactive waste
- Danger of large scale accident

Question 32

What is nuclear fusion

Answer 32

The ionising of two light nuclei to form a heavier more stable nucleus with the release of energy

Question 33

Arguments for nuclear fusion and the difficulties

Answer 33

No greenhouse gases
Renewable
No radioactive waste
Fail safe

Expensive
New technology required
Difficult to heat hydrogen to such temperatures