Answer: Experiments with cathode rays being deflected by a magnetic field (& electric field ) show that cathode rays are composed of particles that are charged.
Explanation:
In a cathode ray experiment there is a tube in which there is an electron gun which ejects electron beam which passes through a grid which constricts them.
Normally when no electric or magnetic field is applied to the beam it goes undeviating which produces luminescence in center only when hits the fluorescent screen. But when subjected to electric and magnetic fields the beam deviates from the straight path and disperses to illuminate the fluorescent screen at various other spots away from the center. This proves that the particles have charge on them.
