Velocity of light in a liquid is `1.5 xx 10^8 ms^(-1)` and in air,it is `3xx10^8 m s^(-1)`.If a ray of light passes from this liquid to air ,calculate the value of critical angle.

Velocity of light in glass in 2 xx 10^8 m s^(-1) and that in air is 3 xx 10^8 m s^(-1) .By how much would an ink dot appear to be raised,when covered by a glass plate 6.0 cm thick?

A ray of light passes from air to glass (mu = 1.5) at an angle of 30^@ .Calculate angle of refraction.

The critical angle of light passing from glass to air is minimum for

Two points charges q_1 = 10 xx 10^-8 c and q_2 = -2 xx 10^-8 C are separated by a distance of 60cm in air. Also calulate the electrostatic potential energy of the system.