A graph is plotted between the angle of deviation $\delta$ in a triangular prism and angle of incidence as shown in the figure. Refracting angle of the prism is: 

Minimum distance between real object and image produced by a concave mirror of focal length 20 cm is:

Three lenses A, B and C are shown in the figure. Lens A is concave lens. B and C are plano-convex lenses. All the lenses have same focal length f. In which case the spherical; aberration is minimum?

A small air bubble is present exactly at the centre of a glass sphere. Size of the image as seen from outside is of

Three identical thin convex lenses are kept as shown in the figure. A ray passing through the lenses is shown. The focal length of each lens is 

An object is at a distance of 30 cm in front of a concave mirror of focal length 10 cm. The image of the object will be:

To a diver inside water, the setting sun will appear at an angle (with the horizontal) of:
 $\left[{\mu }_w=\frac{5}{4}\right]$

In normal adjustment, the angular magnification of an astronomical telescope is 39. If the length of the tube is 2 m, then the focal length of the objective and eyepiece are respectively,

The following diagram shows a glass sphere of radius 10 cm with a paraxial incident ray. The refractive index of the material of the glass is

A convex lens of focal length 10 cm form real image of an object. The distance between the object and the image may be:

A spherical fishbowl of radius 15 cm is filled with water of refractive index $\frac{4}{3}$. A cat standing outside in the air at a distance of 30 cm from the centra of the fishbowl is looking at the fish. At what distance from the centre would the cat appear to fish situated at the centre?

Two convex lenses of focal length X and Y are placed parallel to each other. An object at infinity from the first lens forms its image at infinity from the second lens. The separation between the two lenses should be:

A plano-convex lens of focal length 20 cm is silver painted on its plane, as shown. The distance of the image of object O from the lens-mirror system is:

Two plane mirrors are placed perpendicular to each other as shown in the figure. An object O is kept at the angular bisector of the two mirrors. Numbers of images of object O is formed, will be:

Two convex lenses of focal lengths 10 cm and 30 cm are kept at a separation of 20 cm. Then the correct statement is:

If one surface of a biconvex lens is silvered, then it behaves as

An astronomical telescope has an angular magnification of 20 in its normal adjustment. The focal length of the eyepiece is 4 cm. Distance between objective and eyepiece is:

A liquid of refractive index $\frac{4}{3}$ is placed between two identical planoconvex-lenses touching each other at their spherical surfaces of radius R. If the refractive index of the lens is 1.50, then the lens behaves as:

The thickness of a plano-convex glass lens in the middle is 1.5 cm. Viewing from the flat side the thickness of the lens at the centre will appear (refractive index of glass is 1.5) to be

A ray of light incident on an equilateral prism at an angle of incidence i. The deviation produced by prism will be maximum when angle i is [take ${\mu }_{glass}=2$]

A lens of focal length $f_a$ in air consists of a glass of refractive index ${\mu }_g$. If $f_l$ is its focal length in a liquid of refractive index ${\mu }_l$, then for ${\mu }_l={\mu }_g$ :

If four convex lenses, given to you have focal lengths $f_1<f_2<f_3<f_4$, then which of the following combination will you prefer to form a compound microscope?

A light ray is incident on a prism of refracting angle $30°$. The refractive index of prism is $\sqrt{2}$, then for what value of angle of incidence, the ray will retrace its path?

The ratio of the velocity of light in a medium to the velocity of light in a vacuum is $\frac{4}{5}$. If the ray of light is emerging from this medium into the air, then the critical angle for this interface of medium and air will be:

If light ray is incident normally on face AB of a part of a prism, then for no emergent ray from second face AC [$\mu \to$refractive index of glass of prism]

A plane mirror is fixed in YZ-plane at x = 0. The velocity of a moving object is $\overrightarrow{v_0}=3\hat{i}+6\hat{j}+4\hat{k}$. The velocity of the image relative to a stationary observer will be:

If there is no emergent light through a prism of refracting angle $60°$, whatever may be the angle of incidence, then the minimum value of the refractive index of the material of the prism is

If the space between two convex lenses of glass in the combination shown in the figure below is filled with water, then

A prism of refracting angle $30°$, has one of the refracting faces polished. A beam of light incident on the other refracting face with i = $60°$ will retrace its path, if the refractive index of prism would be

The Refractive index of material of an equilateral prism is $\sqrt{2}$. Angle of incidence for minimum deviation is