A luminous object is paced just below a glass slab of thickness t. A circular opaque disc is placed vertically above on the surface of the glass-slab. If C is critical angle for glass-air interface, then predict the minimum radius of the opaque disc so that the object cannot be seen from any uncovered portion of the glass-slab.

A glass slab of thickness 12 mm is placed on a table .The lower surface of the slab has a black spot.At what depth from the upper surface will th espot appear,when viewed fromo above?The refractive index of glass =1.5.

An object is placed 21 cm in front of a concave mirror of radius of curvature 10 cm.A glass slab of thickness 3 cm and refractive index 1.5 is then placed close to the irror in the space between the object and mirror as shown in Fig.2.62.Find the position of the final image formed.You may take the distacne of the near surface of the slab from the mirror to be 1 cm. .

A ray of light incident on the horizontal surface of a glass slab t 70^@ just grazes the adjacent vertical surface after refraction. Compute the critical angle and refractive index of the glass.

Consider a light beam incident from air to a glass slab at Brewster's angle as shown in Fig. EP 10.1. A polarised is placed in the path of the emergent ray at point P and rotated about an axis passing through the center and perpendicular to the plane of the polaroid.

Consider a ray of light incident from air onto a slab of glass (refractive index n) of width d, at angle theta . The phase difference between the ray reflected by the top surface of the glass and the bottom surface is:

A diverging beam of light from a point source S having divergence angle alpha , falls symmetrically on a glass slab as shown. The angles of incidence of the two extreme rays are equal. If the thickness of the glass slab is t and the refractive index n, then the divergence angle of the emergent beam is .

A spherical surface radius of curvatue R seprates air (refractive index 1.0) from glass 9refractive index 1.5).The centre of curvature is in the glass.A point object P is placed in air is found to have a real image Q in the glass.The line PQ cuts the surface at a point O and PO = OQ[Fig.2.47].Find the distance of object from the shperical surface. .

Classify the objects or materials given below as opaque,transparent or translucent and luminous or non-luminous. Air, water, a piece of rock, a sheet of aluminium, a mirror , a wooden board, a sheet of polythene,a CD ,smoke , a sheet of plane glass, fog, a piece of red hot iron, an umbrella, lighted fluorescent tube , a wall ,a sheet of carbon paper , the flame of a gas burner, a sheet of cardboard, a lighted torch , a sheet of cellophane, a wire mesh, kerosene stove ,sun, firefly, moon.