Nuclear Physics

Question 1

What is the mass number?

Answer 1

Number of protons and neutrons in the nucleus

Question 2

What is the atomic number?

Answer 2

Number of protons/electrons in an atom

Question 3

What are isotopes?

Answer 3

Are atoms of the same element which have a different mass number

Question 4

What does 23Na stand for?

Answer 4

23 is the mass number

Question 5

Give an example of natural nuclear reaction

Answer 5

Nuclear decay

Question 6

Define nuclear decay

Answer 6

It is the process where part of unstable nuclei disintegrated from it and it is emitted as radiation

Question 7

Give examples of artificial nuclear reactions

Answer 7

Fusion and fission

Question 8

Define nuclear fusion

Answer 8

It is the process where two atomic nuclei combine

Question 9

Define fission

Answer 9

It is the process where atomic nucleus splits to other fragments

Question 10

How is radioactivity measured?

Answer 10

In becquerels

Question 11

In alpha decay what happens to the atomic number and mass number?

Answer 11

Mass number decreases by four

Atomic number decreases by 2

Question 12

What is produced in alpha decay?

Answer 12

Helium

Question 13

What is radioactivity?

Answer 13

A random process

Question 14

What is background radiation?

Answer 14

The low intensity present in the Earth’s atmosphere.

Question 15

Give sources of background radiation

Answer 15

Radiation from the earth's crust 
Radiation from outer space
Emission from nuclear experiments and power stations
Building materials
Radon gas

Question 16

How does radioactivity form ions?

Answer 16

When alpha, beta particles or gamma rays collide with a material they knock off an electron

Question 17

What is an ion?

Answer 17

Any atom that has lost or gained electrons

Question 18

What are uses of ionising radiation?

Answer 18

A smoke detector

Question 19

What is the relative charge of alpha particles?

Answer 19

+2

Question 20

What is the speed of alpha?

Answer 20

0.1 speed of light

Question 21

What is the ionizing effect of alpha particles?

Answer 21

Highest ionisation due to frequent collision with gas molecules since they are massive

Question 22

What is the penetrating effect of alpha particles?

Answer 22

Stopped by a sheet of paper or skin

Question 23

What are beta particles?

Answer 23

High energy electrons emitted from the nucleus

Question 24

What is the relative charge of beta particles?

Answer 24

-1

Question 25

What is the ionising effect of beta particles?

Answer 25

Much less ionisation than alpha rays

Question 26

What is the penetrating effect of beta particles?

Answer 26

Stopped by a few mm of aluminium

Question 27

What is gamma rays?

Answer 27

High energy-frequency electromagnetic radiation

Question 28

What is the relative charge of gamma rays?

Answer 28

0

Question 29

What is the ionising effect of gamma rays?

Answer 29

least ionisation effect

Question 30

What is the speed of gamma rays?

Answer 30

Speed of light

Question 31

What is the penetrating effect of gamma rays?

Answer 31

Very high penetration effect can only be stopped by a thick sheet of lead

Question 32

When the current is going down( positive is up, negative is down) what happens when alpha particles are being shot through it?

Answer 32

They will be slightly deflected down

Question 33

When the current is going down( positive is up, negative is down) what happens when beta particles are being shot through it?

Answer 33

They are deflected more up

Question 34

When the current is going down( positive is up, negative is down) what happens when gamma rays are being shot through it?

Answer 34

Nothing happens

Question 35

When the current is going up( positive is down, negative is up) what happens when alpha particles are being shot through it?

Answer 35

They will slightly deflect up

Question 36

When the current is going up( positive is down, negative is up) what happens when beta particles are being shot through it?

Answer 36

They are deflected greatly down

Question 37

What happens in beta radiation?

Answer 37

A neutron in the parent nucleus changes to proton and electron

Question 38

What happens to the mass number and atomic number in beta decay?

Answer 38

The atomic number increases by one

Question 39

What is the half life?

Answer 39

Average time for half of the atoms in a given sample to be decayed or average count rate reduced to half of the original counts

Question 40

What happens in a graph showing count rate?

Answer 40

It decreases

Question 41

What is decay series?

Answer 41

It is one element turning into another which turns into another

Question 42

What are uses of radioactivity?

Answer 42

1. Gamma rays are used to kill bacteria- sterilization 2. Smoke detector 3. Monitor thickness 4. Carbon dating- find the age of living organisms 5. Dating rocks 6. Find leaks/blockages in pipes 7. Tracers to investigate a patient's body 8. Treatment of cancer

Question 43

Which radiation is the most dangerous if the radioactive source is inside the body?

Answer 43

Alpha radiation because it is easily absorbed by cells

Question 44

Which radiation is the most dangerous if the radioactive source is outside the body?

Answer 44

Beta and gamma because they can penetrate through skin