Unit 1 AOS 2: How is energy from the nucleus utilized?

Question 1

Define Isotope

Answer 1

-Isotopes are two nuclei with the same number of electrons, the same numbers of protons, but different numbers of neutrons

-They are chemically identical, but physically different (density, radioactivity)

-A radio-isotope is an unstable isotope that will radioactively decay

Question 2

Types of decay

Answer 2

1. Alpha decay
2. Beta decay (positive and negative)
3. Gamma

Question 3

Define radiation

Answer 3

Energy spreading out from a point source (radiating)

Question 4

Define radioactivity

Answer 4

Energy in unstable atoms being released by the process of nuclear decay

Question 5

Define ionising radiation

Answer 5

Energy spreading out from a point source which is sufficient to ionize atoms when absorbed

Question 6

Activity

Answer 6

Activity is measured in Becquerel’s, the number of ionizing particles detected per second.

1 Becquerel (Bq) = 1 ionizing particle detected per second

𝑀𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 (𝐵𝑞)= (𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠 𝑑𝑒𝑡𝑒𝑐𝑡𝑒𝑑)/(𝑡𝑖𝑚𝑒 (𝑠))

Question 7

Do all alphas have the same energy when nuclei of the same type decay?

Answer 7

When an isotope is unstable and it falls down to a more stable position, it loses the same amount of energy.

So isotopes of the same type will always emit alpha particles with the same energy

Question 8

Do beta particles all have the same energy when the same nucleus type decays?

Answer 8

No. The same isotope can produce beta particles with a range of kinetic energies.

Question 9

Beta minus decay

Answer 9

a down quark in a neutron turns into an up quark resulting in the release of an electron

A beta minus particle is a high energy electron emitted from a nucleus when a neutron turns into a proton

Beta minus decay only occurs when there are too many neutrons in a nuclei to the point of instability

Question 10

Beta plus decay

Answer 10

an up quark in a proton turns into a down quark resulting in the release of a positron (an anti-electron).

A beta plus particle is a high energy anti-electron emitted from a nucleus when a proton turns into a neutron

Beta plus decay only occurs when there are too many protons in a nuclei to the point of instability

Question 11

Gamma decay

Answer 11

Following an alpha or beta decay, the nucleus can be left “excited” i.e. oscillating in a higher energy state. The nucleus can move to a lower energy state by emission of a typically high energy photon (packet of electromagnetic radiation).

There is no change in number of protons or neutrons

Question 12

List the types of radiation from least ionizing to most.

Answer 12

Gamma, beta minus, alpha

Question 13

List the types of radiation from least penetrating to most.

Answer 13

Alpha, beta minus, gamma

Question 14

What is are the speeds of each type of radiation?

Answer 14

Alpha: up to approx. 10% speed of light
Beta: 50-90% speed of light
Gamma: speed of light

Question 15

What are each of the radiation types absorbed by?

Answer 15

Alpha: paper
Beta: Aluminum
Gamma: Lead

Question 16

What is the distance travelled by each type of radiation in air?

Answer 16

Alpha: few cm
Beta: 10s of cm
Gamma: infinite