Separating alpha, beta and gamma

Electric Fields.

The effect of the field depends on the charge of the radiation.

Alpha particles are positively charged and are therefore attracted to the negative plate in an electric field.

Beta particles are negatively charged and are therefore attracted to the positive plate in an electric field.

Gamma rays are unaffected.

Use Fleming's Left Hand Rule (see Electromagnetism Learn-it) to predict behaviour in magnetic fields. The "current" (second finger flow of charged particles) is the beam of radiation. Remember, the second finger shows conventional current so for beta particles point it in the reverse direction to the beam. For alpha particles it points in same direction as beam. Gamma rays have no charge so experience no force.

Note: alpha and beta particles follow circular paths in magnetic fields. The force due to the magnetic field is a centripetal force (see circular motion).