Photo cells are used for the:

Which microscope is used for nanotechnology?

Match List-$I$ (Fundamental Experiment) with List-$II$ (its conclusion) and select the correct option from the choices given below the list.

List-$I$	List-$II$
$a$. Franck-Hertz Experiment	$i$. Particle nature of light
$b$. Photo-electric Experiment	$ii$. Discrete energy levels of atom
$c$. Davisson-Germer Experiment	$iii$. Wave nature of electron
	$iv$. Structure of atom

Energy of an electron and a photon are equal. If the wavelength of the electron is $1\,\mathring{A}$,then the wavelength of the photon is approximately ............. $\mathring{A}$.

The kinetic energy of emitted cathode rays is dependent on:

Find the number of photons emitted per second from a source of light which results in a photocurrent with drift velocity of $1.5 \ m/s$ in a conductor with cross-section area $0.25 \ m^2$ and volume density of electrons $10^{20} \ m^{-3}$. (Assume that $60\%$ of photons emitted result in electron emission).