What is the speed of cathode rays?

How can the mass of an electron be obtained?

Who evaluated the mass of the electron indirectly with the help of its charge?

For a thermionic emitter (metallic),if $J$ represents the current density and $T$ is its absolute temperature,then the correct curve between $\log_e \frac{J}{T^2}$ and $\frac{1}{T}$ is:

The metal which has the highest work function among the following is:

Cathode rays travelling from east to west enter into a region of an electric field directed towards north to south in the plane of the paper. The deflection of cathode rays is towards: