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TYPES OF RADIOACTIVITY

There are three main types of radioactivity: alpha (a) beta(b) gamma(g) The table shows some of their properties


Property Alpha (a) Beta (b) Gamma (g)
Range in air a few cm a few tens of 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 a magnetic field a little a lot none
Speed <1%c 90%c c


[m is the mass of the electron - very small, one electron has a mass of about 10-30 kg!]
(this is an easier way of writing its mass than as 0.000 000 000 000 000 000 000 000 000 001 kg)
[c is the speed of light, 300 000 km/s]

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

A VERSION IN WORD IS AVAILABLE ON THE SCHOOLPHYSICS USB
 
 
 
 
© Keith Gibbs 2020