Wave Optics · Question 3

A solid glass sphere of refractive index n= 3 and radius R contains a spherical air cavity of radius R2, as shown in the figure. A very thin glass layer is present at the point O so that the air cavity (refractive index n=1) remains inside the glass sphere. An unpolarized, unidirectional and monochromatic light source S emits a light ray from a point inside the glass sphere towards the periphery of the glass sphere. If the light is reflected from the point O and is fully polarized, then the angle of incidence at the inner surface of the glass sphere is . The value of is [figure]

In a Young's double slit experiment, a combination of two glass wedges A and B, having refractive indices 1.7 and 1.5, respectively, are placed in front of the slits, as shown in the figure. The separation between the slits is d=2 mm and the shortest distance between the slits and the screen is D=2 m. Thickness of the combination of the wedges is t=12 . The value of l as shown in the figure is 1 mm. Neglect any refraction effect at the slanted interface of the wedges. Due to the combination of the wedges, the central maximum shifts (in mm) with respect to O by [figure]

A point source S emits unpolarized light uniformly in all directions. At two points A and B, the ratio r=IA/IB of the intensities of light is 2. If a set of two polaroids having 45 angle between their pass-axes is placed just before point B, then the new value of r will be .

The 8th bright fringe above the point O oscillates with time between two extreme positions. The separation between these two extreme positions, in micrometer ( m), is .

The maximum speed in m/s at which the 8th bright fringe will move is .