Which scientist invented cathode rays?

Cathode rays are similar to visible light rays in that

Which of the following has the highest specific charge?

The thermionic emission of electrons is due to:

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:

The ratio of thermionic currents $(I/I_0)$ for a metal when the temperature is slowly increased from $T_0$ to $T$ is shown in the figure. ($I$ and $I_0$ are currents at $T$ and $T_0$ respectively). Which curve correctly represents this relationship?