A liquid of refractive index `1.33` is placed between two identical plano-convex lenses, with refractive index `1.50`. Two possible arrangement `P` and `Q` are shown. The system is

A liquid of refractive index 1.33 is placed between two identical plano-convex lenses, with refractive index 1.50 . Two possible arrangement P and Q are shown in figure-. The system is:

A liquid of refractive index 1.6 is introduced between two identical plano-convex lenses in two ways P and Q as shown. If the lens ma terial has refractive index 1.5, the combina tion is

Two identical thin planoconvex lenses of refractive index n are silvered, one on the plane side and other on the convex side. The ratio of their for lengths is

Two identical thin planoconvex lenses of refractive index n are silvered, one on the plane side and other on the convex side. The ratio of their for lengths is

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