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:

In a Thomson set-up for the determination of $e/m$,electrons accelerated by $2.5 \ kV$ enter the region of crossed electric and magnetic fields of strengths $3.6 \times 10^4 \ Vm^{-1}$ and $1.2 \times 10^{-3} \ T$ respectively and go through undeflected. The measured value of $e/m$ of the electron is equal to

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?

Explain the emission of electrons from a metal. Define work function. Write its unit,and state the factors upon which the work function of a metal depends.

Which of the following is not true with respect to cathode rays?

What is the value (magnitude) of the electric field required for field emission?