Deflection in a magnetic field
The animation below shows the deflection of radiation in a magnetic field.
Alpha particles in a magnetic field
When a charged particle cuts through a magnetic field it experiences a force referred to as the motor effect. Alpha particles are deflected by a magnetic field confirming that they must carry a charge. The direction of deflection which can be determined by Fleming’s left hand rule demonstrates that they must be positively charged. Remember for Fleming’s left hand rule the second finger is aligned with the direction of the current which is from positive to negative.
Beta particles in a magnetic field
Beta particles are deflected by a magnetic field in an opposite direction to alpha particles confirming they must hold a charge opposite to alpha particles. Beta particles are fast moving electrons and are thus negatively charged.
Gamma rays in a magnetic field
Gamma rays are unaffected by a magnetic field. This shows gamma rays are uncharged as they do not experience a force when passing through the lines of a magnetic field. Gamma rays are highly energetic waves with no charge associated with them.