The basic principle used behind the working of electron microscope is:

When metal of work function 1.4 eV is exposed to a radiation, the maximum kinetic energy of the electron emitted is 0.4 eV . The stopping potential required is:

The variation of the stopping potential ( $\mathrm{V}_{\mathrm{o}}$ ) with the frequency of incident radiation( $n$ ) is as given below.

[no - threshold frequency. h - Planck's constant e-electronic charge] then the slope of the graph AB with the frequency axis is:

What is the ratio of de Broglie wavelength of an electron to that of proton if the velocity of proton is $\frac{1}{6}$ the velocity of electron?