$A$ convex lens of crown glass $(n = 1.525)$ will behave as a divergent lens if immersed in:

The sun subtends an angle of $0.5^{\circ}$ at the earth's surface. Its image is formed by a convex lens of focal length $50 \ \text{cm}$. The diameter of the image will be (in $\text{mm}$)

$A$ light ray hits the pole of a thin biconvex lens as shown in the figure. The angle made by the emergent ray with the optic axis will be

The relation between $n_1$ and $n_2$,if the behavior of light rays is as shown in the figure,is:

$A$ magnifying lens has a focal length of $10 \, cm$. If an image is to be formed at a distance of $30 \, cm$ from the lens,the object should be placed at a distance of ..... $cm$.

The refractive index of the material of a concave lens is $\mu$. It is immersed in a medium of refractive index $\mu_1$. $A$ parallel beam of light is incident on the lens. The path of the emergent rays when $\mu_1 > \mu$ is