Deflection in an electric field
An insight into the properties of radiation can be demonstrated by observing their behaviour in a magnetic and electric field.
The animation below shows the deflection of radiation in an electric field.
Alpha Particles in an electric field
Alpha particles are attracted to the negatively charged plate. This confirms that they must be positively charged as unlike charges attract. Alpha particles are helium nuclei; they contain 2 protons which gives them their positive charge.
Beta Particles in an electric field
Beta particles are attracted to the positively charged plate. This confirms that they are negatively charged. Beta particles are fast moving electrons with a very low mass and so have a high charge to mass density. They are deflected much more than the heavier alpha particles.
Gamma rays in an electric field
Gamma rays are unaffected by an electric field. This shows gamma rays are uncharged. Gamma rays are highly energetic waves with no charge associated with them.