Question

What are the Cathode Rays?

Answer 1

$\text{Cathode rays are fast moving electrons.}$

When energetic radiation is incident on the surface of some metals $\text{whose work function is less than energy of a photon of the radiation}$ then the metals emits energetic electrons

called $photo$ $electrons$ and their beam is called $cathode$ rays.

Cathode rays are moving electrons so they can $ionize$ gas atoms when passed through them.

If the $de-Broglie$ wavelength is equivalent to $thickness$ of a sheet they can penetrate that sheet.