ICSE Class 8 Answered

Discovery of protons:

A German scientist, E. Goldstein in 1886, modified the discharge tube and passed electric current through it.

He found that the positively charged rays were emitted from the anode in the discharge tube. These rays were called canal rays.

When an electric field was applied, these rays deflected towards the negatively charged plate. Thus, Goldstein concluded that an atom contains positively charged particles along with electrons.

These positively charged particles were named as protons by a British scientist, Ernest Rutherford.

Canal rays were also called anode rays since they were emitted from the anode (electrode connected to the positive terminal of high voltage source) in the gas discharge experiments using a perforated cathode.