Spark image
Types of radioactivity
There are three main types of radioactivity: alpha (a) beta (b) gamma (g)

Property Alpha (a) Beta (b) Gamma (g)
Range in air a few cm many cm metres
Ionising ability large small very small
Stopped by paper mm of aluminium cm of lead
Charge +2e -e 0
Mass 8000m m 0
Deflection by magnetic field a little a lot none
Speed <1%c 90%c c

[m is the mass of the electron - about 10 -30 kg!] [c is the speed of light, 300 000 km/s]

Experiments have identified the three types of radiation as:
Alpha – two protons and two neutrons (the nucleus of a helium atom)
Beta – high speed electrons
Gamma – very short wavelength electromagnetic radiation
 
 
 
© Keith Gibbs 2009