Write the formula of focus distance for a thin lens in terms of refractive index and radii of curvature.

The figure below shows a thin plano-convex lens of refractive index mu_(1) and a thin plano-concave lens of refractive index mu_(2) , both having same radius of curvature R of their curved surfaces. Another thin lens of refractive index mu_(3) has same radius of curvature R on the two surface between the plano-convex and plano-concae lenses that the plane surfaces are parallel to each other. Find the focal length of the combination.

The adjacent figure shows a thin plano-convex lens of refractive index mu_1 and a thin plano-concave lens of refractive index mu_2 , both having same radius of curvature R of their curved surfaces. The thin lens of refractive index mu_3 has radius of curvature R of both its surfaces. This lens is so placed in between the plano-convex and plano-concave lenses that the plane surfaces are parallel to each other. The focal length of the combination is

A thin bi-convex lens made up of glass of refractive index 3//2 is placed is front of a plane mirror. The space between the lens and the mirror is filled with water of refractive index 4//3 . The radii of curvatures of the lens are R_(1)=15cm and R_(2)=25 cm . A point object is placed at distance x from the surface whose curvature is R_(1) . The distance x is greater than the separation between the lens and the mirror. Find the value of x so that image must coincide with the object.

The refractive index of a converging lens is 1.4. What will be the focal length of this lens if it is placed in a medium of same refractive index? Assume the radii of curvature of the faces of lens are R_(1) and R_(2) respectively.

Radii of curvature of a canverging lends are in the ration 1:2. Its focal length is 6cm and refractive index is 1:5. Then, its radii of curvature are…

Radii of curvature of a converging lens are in the ratio 1 : 2 . Its focal length is 6 cm and refractive index is 1.5 . Then its radii of curvature are

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

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?

A double convex thin lens made of glass (refractive index mu = 1.5 ) has both radii of curvature of magnitude 20 cm . Incident light rays parallel to the axis of the lens will converge at a distance L such that