Figure 9.35 shows a cross-section of a glass fibre of refractive index 1.68. The outer covering of the pipe is made of a material of refractive index 1.44. What is the range of the angles of the incident rays with the axis of the pipe for which total reflections inside the pipe take place, as shown in the figure. :

A right angled isosceles glass prism is made from glass of refractive index 1.5.Show that a ray of light incident normally on one of the equal sides of this prism is deviated through 90^@ .

A ray of light incident at an angle theta on a refracting face of a prism emerges from the other face normally. If the angle of the prism in 5^@ and the prism is made of a material of refractive index 1.5, the angle of incidence is:

A right angled isosceles glass prism is made from glass of refractive index 1.5.Show that a ray of light incident normally on the hypotneuse of this prism is deviated through 180^@ .

A ray of light falls on a transparent glass slab of refracative index 1.62. If the reflected ray and refracted rays are mutually perpendicular. What is the angle of incidence? Give calculations.

A prism is made of glass of unknown refractive index. A parallel beam of light is incident on a face of the prism. The angle of minimum deviation is measured to be 40^@ . What is the refractive index of the material of the prism? The refracting angle of the prism is 60^@ . If the prism is placed in water (refractive index 1.33), predict the new angle of minimum deviation of a parallel beam of light.

A narrow beam of light is incident normally on one face of a glass prism having refractive index 1.48 . Find the angle of prism if the ray makes a grazing emergence along the other face. Draw a diagram showing the path of rays.

Glass of refractive index 1.5 is coated with a thin layer of thickness t and refractive index 1.8 . Light of wavelength lambda travelling in air is incident normally on the layer. It is partly reflected at the upper and the lower surfaces of the layer and the two reflected rays interface . If lambda = 648 nm , obtain the least value of t ("in" 10^(-8)m ) which the rays interface constructively.

The figure TBQ 9.38 shows an equiconvex lens (of refractive index 1.50) in contact with a liquid layer on top of a plane mirror. A small needle with its tip on the principal axis is moved along the axis until its inverted images if found at the positions of hte needle. The distance of the needle from the lens is measured to be 45.0 cm. The new distane is measured to be 30.0 cm. What is the refractive index of the liquid?

A rectangular glass block of thickness 10 cm and refractive index 1.5 is placed over a small coin.A beaker is filled with water of refractive index 4//3 to a height of 10 cm and is placed over a small block. If the eye is slowly moved away from the normal at a certain position,the coin is found to diappear due to total internal reflection.At what surface does it happen and why? .