A beam of light travelling in water strikes a glass plate which is also immersed in water. When the angle of incidence is $60^{\circ}$, the reflected beam is found to be plane polarised. Find the refractive index of glass, if refractive index of water is $\sqrt{2}$.

In a Young's double slit experiment for a particular wavelength of light the distance between third dark and fifth bright fringe is 1.63 mm . If the distance between two slit is 1 mm and distance between slit and screen is 1 metre. Then, the wavelength of light is

Young's double slit experiment is performed in a medium of refractive index of 1.33 . The maximum intensity is $ I_{0} $. The intensity at a point on the screen, where path difference between the light coming out from slits is $ \frac{\lambda}{4} $, is

In YDSE, monochromatic light falls on a screen 1.80 m from two slits separated by 2.08 mm . The first and second order bright fringes are separated by 0.553 mm . The wavelength of light used is