Two symmetric double convex lenses A and B have same focal length but the radii of curvature differ so that `R_(A) = 0.9R_(B)`. If refractive index of A is 1.63 find the refractive index of B.

A double convex lens has focal length 25 cm. The radius of curvature of one of the surfaces is double of the other. Find the radii, if the refractive index of the material of the lens is 1.5.

The radii of curvatures of a convex lens are 0.04 m and 0.04m. Its refractive index is 1.5. Its focal length is

A double convex lens has a focal length of 25 cm in air. When it is dipped into a liquid of refractive index 4/3. its focal length is increased to 100 cm. Find the refractive index of the lens material.

The focal length of a double convex lens is equal to radius of curvature of either surface. The refractive index of its material is

Assertion : A concave mirror and convex lens both have the same focal length in air. When they are submerged in water, they will have same focal length. Reason refractive index of water is smaller than be refractive index of air.

The focal length of a plano-convex lens is equal to its radius of curvature. The value of the refractive index of its material is

A double convex thin lens made of the refractive index 1.6 has radii of curvature 15 cm each. What is the focal length (in cm) of this les when immersed in a fluid of refractive index 1.63?

The two spherical surfaces of a double concave lens have the same radius of curvature R, and the refractive index of the medium enclosed by the refracting surfaces is mu then the focal length of the lens is

A double convex thin lens made of the refractive index 1.6 has radii of curvature 15 cm each. The focal length of this lens when immersed in a fluid of refractive index 1.63, is