Topic 36

Question 1

What is the radioactivity decay law?

Answer 1

Decay of an unstable nucleus plus the associated radiations

Question 2

Give the equation to calculate the decay constant

Answer 2

λ = Decay Constant

Question 3

Give the Half-Life equation

Answer 3

Question 4

Give the equation giving the Effective half-life and the Biological Half Life

Answer 4

T_b = Biological Half life

T_eff = Effective half life

Question 5

Describe radiocarbon dating

Answer 5

¹⁴C is present in the environment.

When organism dies, the ¹⁴C intake sops and decays.

The date of death can be calcualted from this

Question 6

What is a nuclear reaction?

Answer 6

A nucleus is changed by the interaction with another nuclear particle

E.g Neutron + ¹⁴N → ¹⁴C + proton

Question 7

Describe a chain reaction

Answer 7

A neutron divides a large atom, e.g ²³⁵U

This releases energy and more neutrons, giving rise to more divisions.

Can be controlled or sudden

Question 8

Give a sudden chain reaction

Answer 8

Nuclear Weapons

Question 9

Give a controlled chain reaction

Answer 9

Nuclear reactors

Question 10

Describe the transmission of Alpha radiation

Answer 10

Travels in a straight line

34 eV required in air to create an ion pair

Question 11

Describe the transmission of beta radiation

Answer 11

Travel in a zig-zig pattern

Longer range than Alpha particles

Higher speed than alpha particles

Question 12

Describe the transmission of gamma radiation

Answer 12

Highly penetrating

Penetration is characterised by the half thickness

(Distance to where their intensity falls to the half)

Question 13

Describe the main feature of neutron radiation

Answer 13

Indirect ionisation

(Recoiled neutrons of hit atoms will ionise)