What experiment did j. j thomson do?
a) he suspended charged oil drops in a chamber
b) he shot alpha particles through golf foil
c) he sent a cathode ray between electrically charged metal plates
d) he hit metal plates with light

Option(c)

He sent a cathode ray between electrically charged metal plates

Explanation:

In 1897, physicis JJ Thomson experimented with a device called CRT(cathode ray tube) in which a current passed through gases at a low pressure. A CRT(cathode ray tube) comprises of a sealed glass-duct fitted with electrodes at both ends of the metal disks.

Then the electrodes are connected to an electricity source. One electrode,  known as  anode, will be charged positively while the other electrode, referred as cathode, will be charged negatively. A light beam passes from the cathode to the anode which is called as the cathode ray.