In figure, the optical fiber is l = 2 m long and has a diameter of `d = 20 mum.` If a ray of light is incident on one end of the fiber at angle `theta_1=40^@` , the number of reflections it makes before emerging form the other end is close to : (refractive index of fiber is 1.31 and `sin40^@=0.64`)

Two parallel plane mirrors M_(1) and M_(2) have a length of 2 m each and are 10 mm apart. A ray of light is incident on one end of mirror M_(2) at an angle of 30^(@) . The number of reflections light undergoes before reaching the other end is –

Two plane mirrors M_(1) and M_(2) each have length 1 m and are separated by 1 cm . A ray of light is incident on one end of mirror M_(1) at angle 45^(@) . How many reflections the ray will have before going from the other end?

Two plane mirrors each 1.6 m long, are facing each other. The distance between the mirrors is 20 cm. A light incident on one end of one of the mirrors at an angle of incidence of 30^(@) . How many times is the ray reflected before it reaches the other end?

An optical fiber has index of refraction n=1.40 and diameter d=100 mu m . It is surrounded by air. Light is sent into the fiber along the axis as shown in figure. If smallest outside radius R permitted for a bend in the fiber for no light to escape is given by 50 x ("in" mu m) fill value of x.

An optical fiber has index of refraction n=1.40 and diameter d=100 mu m . It is surrounded by air. Light is sent into the fiber along the axis as shown in figure. If smallest outside raidus R permitted for a bend in the fiber for no light to escape is given by 50 x (in mu m) fill value of x.

What is the least radius through which an optical fiber of core diameter 0.05 mm may be bent (as shown in figure) without serious loss of light? The refractive index of the core is 1.6 and that of cladding is 1.5.

An equiconvex lens has its two surfaces of radius of curvature R = 10 cm . Thickness of the lens at its centre is 2 cm. A light ray is incident making an angle of 2° with the optic axis of the lens. Find the angle that the emergent ray will make with the optic axis. The refractive index of all media is as marked in the Figure.