P4 : Radioactivity

Question 1

Radioactivity

Answer 1

Some isotopes have an unstable nucleus
To become stable, the nucleus gives out radiation
This is called radioactive decay
Radioactive decay is a random process

Question 2

Activity

Answer 2

Activity is the rate at which a source of unstable nuclei decay
Activity is measured in becquerel (Bq)
1 Bq = 1 decay per second

Question 3

How do we measure activity

Answer 3

We can use a Geiger - muller tube

Question 4

What is the count rate

Answer 4

The number of decays recorded each second by a detector

Question 5

Alpha particle

Answer 5

An alpha particle is the same as a Helium nucleus

Question 6

Beta particle

Answer 6

A beta particle is an electron which is ejected from the nucleus at a very high speed
Since the nucleus doesn’t contain electrons, beta particles are formed inside the nucleus when neutron changes into a proton and electron

Question 7

Gamma radiation

Answer 7

Gamma rays are a type of electromagnetic radiation from the nucleus

Question 8

Neutron radiation