Given the value of the ground state energy of hydrogen atom as –13 �6 eV, find out its kinetic and potential energy in the ground and second excited states.

A ray of light incident on an equilateral glass prism propagates parallel to the base line of the prism inside it. Find the angle of incidence of this ray. Given refractive index of material of glass prism is .

OR

A biconvex lens of glass of refractive index 1 �5 having focal length 20 cm is placed in a medium of refractive index 1 �65. Find its focal length. What should be the value of the refractive index of the medium in which the lens should be placed so that it acts as a plane sheet of glass?

Determine the value of the de Broglie wavelength associated with the electron orbiting in the ground state of hydrogen atom (Given eV and Bohr radius Å). How will the de Broglie wavelength change when it is in the first excited state?

Distinguish between ‘sky wave’ and ‘space wave’ modes of propagation. Why is the sky wave mode of propagation restricted to frequencies up to 40 MHz?

In the potentiometer circuit shown, the null point is at X. State with reason, where the balance point will be shifted when

(a)resistance R is increased, keeping all other parameters unchanged;

(b) resistance S is increased, keeping R constant.