A point object O is placed in fornt of a transparent slab at a distance x from its surface. It is seenfrom the other side of he slab by light incident nearlyl normally to the slab. The thickness of the slab is t and its refractive index is `mu`. Show that the apparent shift in the position of the object is independent of x and find its value.

An air bubble in glass slab of refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness of the slab is,

The thickness of a glass slab is 0.25 m. It has a refractive index of 1.5 A ray of light is incident on the surface of the slab at an angle of 60^(@) . Find the lateral displacement of the light when it emerges from the other side of the mirror.

An object P is focussed by a microscope M. A glass slab of thickness 2.1 cm is introduced between P and M. If the refractive index of the slab is 1.5, by what distance should the microscope be shifted to focus the object again ?

An object is placed 21 cm in fron of a concave mirror of radius of curvature 20 cm.A glass slab of thicknes 3 cm and refractive index 1.5 is palced close to the mirror in the space between the object and the mirror. Find the position of the final image fromed. The distance of the nearer surface of the slab from the mirror is 10 cm.

(i) Keep a glass slab on a blank paper and draw its outline PQRS as shown in the figure. (ii) Draw an inclined straight line on the side of PQ so that it intersect PQ at N. Pierce two pins vertically at two points A and B along the line. (iii) Look at the pins A and B from the opposite side of the slab and pierce pins C and D vertically so that the images of A and B are in line with C and D. (iv) Now remove the chip and the pins and draw a straight line going through points C and D so that it intersects SR at M. (v) Join points M and N. Observe the incident ray AN and emergent ray MD. Questions: (a) What is your observation about the emergent ray and incident ray ?

The illuminance of a small area changes from 900 lumen m^-2 to 400 lumen m^-2 when it is shifted along its normal by 10 cm. Assuming that it is illuminated by a point source placed on the normal, find the distance between the source and the area in the original position.