Properties of Alpha Beta and Gamma radiation (3.3)

Question 1

What to alpha particles consist of?

Answer 1

2 protons and 2 neutrons

Question 2

What is the charge of an alpha particle?

Answer 2

Double postive charge

Question 3

What is the charge of a beta particle

Answer 3

+1 (Beta plus) or -1 (Beta minus)

Question 4

What is the speed of beta particles

Answer 4

Lighter than alpha particles and thus travel at 90% of the speed of light

Question 5

What is the speed of alpha particles

Answer 5

Quite heavy and thus travel at appx. 10% of the speed of light or Twenty thousand kms-1 or 2 x 10^7 ms-1

Question 6

What speed do gamma rays travel at?

Answer 6

Travel at the speed of light 3.0x10^8 ms-1

Question 7

What is the charge of gamma rays

Answer 7

Are uncharged particles

Question 8

Organise the following in decreasing penetrative power
Alpha, Beta and Gamma

Answer 8

Gamma, Beta, Alpha

Question 9

Organise the following in decreasing ionising power
Beta, Alpha, Gamma

Answer 9

Alpha, Beta, Gamma

Question 10

Why do Alpha particles have low penetrative power?

Answer 10

They travel through space low speeds, and due to the double + charge, they ionise with the air. Its charge, ionising power and low speed make it very easy to stop. Meaning alpha particles have a low penetrative power

Question 11

A radiographer inserts a wire into a breast cancer to destroy the cancerous cells close to the wire. Should this wire be an alpha, beta or gamma emitter? Explain your reasoning

Answer 11

The emitter should be a beta emitter. An alpha emitter would not have sufficient penetrating power, while a gamma emitter would irradiate and kill surrounding healthy cells

Question 12

Explain why beta particles, not alpha particles or gamma rays are the best to use for monitoring the thickness of metal sheets

Answer 12

Beta particles should be used. Alpha particles wouldn’t be able to penetrate the metal. Gamma particles would pass through the metal. Differences in thickness of material would not affect the count rates in a geiger counter. Beta particles will pass through the metal, so for a set thickness of metal, a set number of beta particles should make it to the other side. Any anomaly would be recorded in the geiger counter.

Question 13

What is an electron volt

Answer 13

An electron volt is the energy that an electron would gain if it were accelerated by a potential difference of 1 volt.

Question 14

What is one electron volt in joules

Answer 14

1.6 x 10-19

Question 15

Order the 3 types of radiation from heaviest to lightest

Answer 15

Alpha, Beta, Gamma

Question 16

Look at table on page 66 on textbook and copy table

Answer 16

DO IT.

Question 17

Give an example of an isotope that emits or undergoes alpha radiation and its use

Answer 17

Americium 241 (Atomic no. 95) -> used in ionisation smoke detectors

Question 18

Define Penetrative ability

Answer 18

In physics, the ability for radiation to ‘go through’ matter/substances

Question 19

Define Ionising ability

Answer 19

The capability of an atom/particle to remove electrons in the matter/substance it travels through

Question 20

Why do beta minus particles have weak penetrative power

Answer 20

Beta minus particles have weak penetrative power as they are negatively charged and are repelled by the electron cloud of the atoms they interact with.

Question 21

Why do beta minus particles have lower ionising energy than alpha particles

Answer 21

They have a low ionising energy as they lose less energy per collision than alpha particles

Question 22

Describe the penetrative and ionising ability of gamma particles

Answer 22

Gamma particles have a high penetrative ability and poor ionising energy

Question 23

Describe the effect of electric and magnetic fields on Beta, Gamma and Alpha radiation

Answer 23

Electric fields can accelerate charged particles. Therefore, beta and gamma particles when put in an electric field will be accelerated. Gamma particles on the other hand will be unaffected as they are neutral (no charge)