In a Young's double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm wavelength is used. If the wavelength of light is changed to 400 nm, then the number of fringes he would observe in the same region of the screen is

A light ray falls on a glass surface of refractive index $$\sqrt3$$, at an angle 60$$^\circ$$. The angle between the refracted and reflected rays would be

When light propagates through a material medium of relative permittivity $$\varepsilon $$_{r} and relative permeability $$\mu$$_{r}, the velocity of light, v is given by (c-velocity of light in vacuum)

Two transparent media A and B are separated by a plane boundary. The speed of light in those media are 1.5 $$\times$$ 10^{8} m/s and 2.0 $$\times$$ 10^{8} m/s, respectively. The critical angle for a ray of light for these two media is