Topic 7 - Radioactivty and particals

Question 1

What is alpha?

Answer 1

particle
- is a helium nucleus, two protons and two neutrons. It has a large mass, compared to other ionising radiations, and a strong positive charge.

Question 2

What is beta?

Answer 2

particle
- is a fast moving electron. It has a very small mass and a negative charge.

Question 3

What is gamma?

Answer 3

is a high-energy electromagnetic wave.
Gamma rays
are caused by changes within the nucleus. They are part of the
electromagnetic spectrum
and so travel at the speed of light. They have no mass and no charge.

Question 4

Alpha range of absorption?

Answer 4

3-5cm

Question 5

beta range of absorption?

Answer 5

15cm

Question 6

gamma range of absorption?

Answer 6

very far

Question 7

alpha ionising power?

Answer 7

high

Question 8

beta ionising power?

Answer 8

medium

Question 9

gamma ionising power?

Answer 9

little

Question 10

Can pass through paper? alpha

Answer 10

no

Question 11

Can pass through paper? beta

Answer 11

yes

Question 12

Can pass through paper? gamma

Answer 12

yes

Question 13

Can pass through 5mm of aluminium - alpha

Answer 13

no

Question 14

Can pass through 5mm of aluminium - beta

Answer 14

no

Question 15

Can pass through 5mm of aluminium - gamma

Answer 15

yes

Question 16

Can pass through 5cm of lead? alpha

Answer 16

no

Question 17

Can pass through 5cm of lead? beta

Answer 17

no

Question 18

Can pass through 5cm of lead? gamma

Answer 18

no

Question 19

Speed - alpha

Answer 19

slow

Question 20

Speed - beta

Answer 20

medium

Question 21

Speed - gamma

Answer 21

fast

Question 22

what is a half life?

Answer 22

the time required for a quantity (of substance) to reduce to half of its initial value.

Question 23

uses of radioactivity? (6)

Answer 23

Food irradiation
Gauging and Thickness control

Tracers in medicine and in industry

Radiotherapy
Smoke detectors
Radioactive dating

Question 24

measure of radioactivity?

Answer 24

Becquerel (Bq).

Question 25

Nuclear fusion?

Answer 25

Nuclear fusion is when two small, light nuclei join together to make one heavier nucleus and become more stable. Fusion reactions occur in stars where, for example, two hydrogen nuclei fuse together under high temperatures and pressure to form a nucleus of a helium isotope.

Question 26

Nuclear fission?

Answer 26

The splitting of a large nucleus to produce two daugther nuclei. Two or three neutrons are also released in the process. The energy from the neutrons powers a nuclear reactor.

Question 27

Similarities of nuclear fission and fusion? (2)

Answer 27

• Both have a change in the nuclei
• Both release energy

Question 28

differances of nuclear fission and fusion? (2)

Answer 28

• Fusion involves the smallest nuclei coming together to make a larger nucleus.
• Fission involves the largest nuclei splitting into two smaller nuclei

Question 29

Where nuclear fusion happens:

Answer 29

Fusion only occurs here naturally because of the extremely high temperature and pressure. This is required because the nuclei are both positively charged.