Power Of Lens And Mirror MCQ - Practice Questions with Answers

One plano-convex and one plano-concave lens of same radius of curvature 'R' but of different materials are joined side by side as shown in the figure. If the refractive index of the material of 1 is ${\mu }_1$ and that of 2 is ${\mu }_2$, then the focal length of the combination is:

A person can see clearly objects only when they lie between 50 cm and 400 cm from his eyes. In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens, the person has to use, will be

For a normal eye, the cornea of the eye provides a converging power of 40 D, and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated by:

A plano convex lens fits exactly into a plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices ${\mu }_1$ and ${\mu }_2$ and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is :

Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index 1.7. The focal length of the combination is:

An achromatic convergent doublet has the power of +2D. If the power of the convex lens is + 5D, then the ratio of the dispersive powers of convergent and divergent lenses will be

A convergent lens of 6 diopters is combined with a diverging lens of -2 diopters. Find the power of combination.

An achromatic convergent doublet has the power of +2D. If the power of the convex lens is + 5D, then the ratio of the dispersive powers of convergent and divergent lenses will be:

The power of a convex lens is . When this lens is immersed in a liquid of refractive index ,  it acts like a divergent lens of focal length . Then refractive index of the liquid will be