A convex lens made of material of refractive index n 2 is kept in a medium of refractive index n1. A parallel beam of light is incident on the lens. Compare the path of rays of light emerging from the convex lens if (i) n1 < n2 (ii) n1 = n2 (iii) n1 > 1.

Q. A concave lens made of a material of refractive index $n_1$ is kept in a medium of refractive index $n_2$. A parallel beam of light is incident on the lens. Complete the path of rays of light emerging from the concave lens if:
(a) $n_1>n_2$ and (b) $n_1<n_2$.
[5 MARKS]

Q. In the given arrangement, a lens of refractive index $1.5$ is placed having medium of refractive indices $n_1$ and $n_2$ on either sides as shown. The values of $n_1$ and $n_2$ respectively with respect to the lens are

Q. A hollow double concave lens is made of very thin transparent material. If can be filled with air or either of two liquids $L_1$ or $L_2$ having refractive indices $n_1$ and $n_2$, respectively $(n_2>n_1>1)$. The lens will diverge parallel beam of light if it is filled with

Q. When a lens of refractive index $n_1$ is placed in a liquid of refractive index $n_2$, the lens looks to be disappeared only, if

Q. Draw a ray diagram showing the formation of the image by a point object on the principal axis of a spherical convex surface separating two media of refractive indices $n_1$ and $n_2$, when a point source is kept in rarer medium of refractive index $n_1$. Derive the relation between object and image distance in terms of refractive index of the medium and radius of curvature of the surface.
Hence obtain the expression for lens-maker's formula in the case of thin convex lens.