P7

Question 1

what happens to nuclei with too many or too few neutrons ?

Answer 1

Nuclei with too many, or too few, neutrons do exist naturally but are unstable and will decay, in a random process, emitting radiation.

Question 2

Types of radioactive decay ?

Answer 2

An unstable nucleus can decay by emitting an alpha particle, a ß- (beta minus) particle, a ß+ (positron), a gamma ray or in some cases a single neutron.

Question 3

Alpha
how penetrating ?
ionising power ?
can travel ?

Answer 3

skin/paper
high
less than 5cm

Question 4

Beta
penetrating ?
ionising ?
travel ?

Answer 4

3mm aluminium foil
low
about 1metre

Question 5

Gamma
penetrating ?
ionising?
travel ?

Answer 5

lead/concrete
very low
ab a km

Question 6

what detects all type of radioactive decay ?

Answer 6

All types of radioactive decay can be detected by photographic film, or a Geiger-Muller tube

Question 7

hows a geiger muller tube work

Answer 7

The Geiger-Muller tube is a device that detects radiation. It gives an electrical signal each time radiation is detected. These signals can be converted into clicking sounds, giving a count rate in clicks per second or per minute.