What should be the value of distance d so that final image is formed on the object itself. (Focal lengths of the lenses are written on the lenses). 



Correct option is

10 cm



A ray of light in incident on a medium with angle of incidence i and refracted into a second medium with angle of refraction r. the graph of sin(i) vs sin (r) is shown in fig. Then, the velocity of light in the first medium in n times the velocity of light in the second medium. What should be the value of n?



A beam of light propagates through a medium 1 and falls onto another medium 2, at an angle α1 as shown in fig. After that, in propagates in medium 2 at to an angle α2 as shown. The light’s wavelength in medium 1 is λ1. What  is the wavelength of light in medium 2?    



You are given two identical plano-convex lenses. When you place an object 20 cm to the left of a single plano-convex lens, the image appears 40 cm to the right of the lens. You then arrange the two plano-convex lenses back to back to form a double convex lens. If the object is 20 cm to the left of this new lens, what is the approximate location of the image?



Light from a denser medium 1 passes to a rarer medium 2. When the angle of incidence is θ the partially reflected and refracted rays are mutually perpendicular. The critical angle will be    


A man is walking under an inclined mirror at a constant velocity V ms–1along the X-axis. If the mirror is inclined at an angle θ with the horizontal, then what is the velocity of the image?



Figure shows the graph of angle of deviation δ versus angle of incidence ifor a light ray striking a prism. The prism angle is



Light is incident on a glass block as shown in fig. If θ1 is increased slightly, what happens to θ2



A thin equiconvex lens (μ = 3/2) of focal length 10 cm is cut and separated and a material of refractive index 3 is filled between them. What is the focal length of the combination? 



Behind a thin converging lens having both the surfaces of the same radius 1 cm, a plane mirror has been placed. The image of an object at a distance of 40 cm from the lens is formed at the same position. What is the refractive index of the lens?



A car fitted with a convex mirror of focal length 20 cm. A second car 2 m broad and 1.6 m high is 6 m away from the first car. The position of the second car as seen in the mirror of the first car is