Radioactivity

Question 1

What is radioactivity

Answer 1

The spontaneous breaking up of an unstable nucleus with the emission of one or more types of radiation

Question 2

Who discovered radioactivity/radiation

Answer 2

Henri becquerel while working on uranium salts

Question 3

What detects radiation

Answer 3

Geiger-muller tube

Question 4

What elements did the curies discover

Answer 4

Polonium 84 and radium 88

Question 5

Describe alpha particles properties

Answer 5

Composition:2 protons + 2 neutrons I.e. He nucleus
Penetrating power: few cm of air
Source: americium 241
Use: smoke alarm

Question 6

Describe beta particles properties

Answer 6

Composition: high energy electrons emitted from nucleus
Penetrating power: 5mm Al
Source: carbon 14
Use: carbon dating

Question 7

Describe gamma rays properties

Answer 7

Composition: electromagnetic radiation
Penetrating power: few cm lead
Source: cobalt 60
Use: killing tumours

Question 8

What are radioisotopes

Answer 8

An isotope that is radioactive

Question 9

What is half life

Answer 9

The time it takes for half the nuclei in a radioactive sample to decay

Question 10

What are the uses of radioactivity

Answer 10

Archaeological - carbon dating- carbon 14 in living tissue. The ratio of carbon12:carbon24 is constant in living tissue. After death carbon14 decays and the proportion of carbon14 drops in proportion to time elapsed

Medical- killing tumours and sterilising surgical equipment Cobalt60

Food irradiation- increases shelf life cobalt60