A room (cubical) is made of mirrors. An insect is moving along the diagonal on the floor

such that the velocity of image of insect on two adjacent wall mirrors is $10 cm{s}^{-1}$. The

velocity of image of insect in ceiling mirror is

A glass prism $\left(\mu =1.5\right)$ is dipped in water $\left(\mu =4/3\right)$ as shown in figure. A light ray is incident normally on the surface AB. It reaches the surface BC after totally reflected, if

(a) $\sin \theta \ge \raisebox{1ex}{$ 8$}\!\left/ \!\raisebox{-1ex}{$9$}\right.$                            (b) $\raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right.<\sin \theta <\raisebox{1ex}{$ 8$}\!\left/ \!\raisebox{-1ex}{$9$}\right.$

(c) $\sin \theta \le \raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right.$                            (d) It is not possible

A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with the distance d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then distance d in cm will be 

A medium shows relation between i and r as shown. If speed of light in the medium is nc then value of n is

For a concave mirror, if the virtual image is formed, the graph between m and u is of the form :

For a convex lens, the distance of the object is taken on X-axis and the distance of the image is taken on Y-axis, the nature of the graph so obtained is :

The diameter of a plano-convex lens is 6 cm and thickness at the centre is 3 mm. If the

speed of light in the material of the lens is $2\times {10}^8\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$sec$}\right.$, the focal length of the lens is

A luminous object is placed at a distance of 30 cm from the convex lens with a focal length of 20 cm. On the other side of the lens, at what distance from the lens, a convex mirror with a radius of curvature of 10 cm be placed in order to have an upright image of the object coincident with it?

Shown in the figure here is a convergent lens placed inside a cell filled with a liquid. The lens has focal length + 20 cm when in air and its material has refractive index 1.50. If the liquid has refractive index 1.60, the focal length of the system is

Which one of the following spherical lenses does not exhibit dispersion? The radii of curvature of the surfaces of the lenses are as given in the diagrams

The size of the image of an object, which is at infinity, as formed by a convex lens of

focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the

convex lens and the image is at a distance of 26 cm from the convex lens, calculate the

new size of the image.

An achromatic prism is made by crown glass prism $\left(A_c=19°\right)$ and flint glass prism

$\left(A_F=6°\right)$. If ${}_C\mu _v=1.5$ and ${}_F\mu _v=1.66$, then resultant deviation for red coloured ray will

be

An isosceles prism of angle 120° has a refractive index of 1.44. Two parallel

monochromatic rays enter the prism parallel to each other in air as shown. The rays

emerging from the opposite faces :

A ray of light is incident on the hypotenuse of a right-angled prism after travelling parallel

to the base inside the prism. If $\mu$ is the refractive index of the material of the prism, the

maximum value of the base angle for which light is totally reflected from the hypotenuse

is 

A plano-convex lens when silvered in the plane side behaves like a concave mirror of

focal length 30 cm. However, when silvered on the convex side it behaves like a concave

mirror of focal length 10 cm. Then the refractive index of its material will be 

A ray of light travels from an optically denser to rarer medium. The critical angle for the

two media is C. The maximum possible deviation of the ray will be

A point object is moving on the principal axis of a concave mirror of focal length 24 cm towards the mirror. When it is at a distance of 60 cm from the mirror, its velocity is 9cm/sec. What is the velocity of the image at that instant?

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is

If an object moves towards a plane mirror with a speed v at an angle $\theta$ to the

perpendicular to the plane of the mirror, find the relative velocity between the object and

the image

To an astronaut in a spaceship, the sky appears:

A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle $\theta$, the spot of light is found to move through a distance y on the scale. The angle $\theta$ is given by 

Two identical glass $\left({\mu }_g=3/2\right)$ equi-convex lenses of focal length $f$ each are kept in contact. The space between the two lenses is filled with water $\left({\mu }_w=4/3\right)$. The focal length of the combination is

(a)  $f/3$             (b) $f$

(c) $\frac{4f}{3}$               (d) $\frac{3f}{4}$

An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and  3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is

An astronomical telescope has an objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance of :

Match the corresponding entries of Column 1 with Column 2. [Where m is the magnification produced by the mirror]
Column 1                         Column 2 
A. m=-2                     a. Convex mirror   
B. m=-1/2                  b. Concave mirror
C. m=+2                    c. Real image
D. m=+1/2                 d. Virtual Image

The angle of incidence for a ray of light at a refracting surface of a prism is 45°. The angle of prism is 60°. If the ray suffers minimum deviation through the prism, the angle of deviation and refracting index of the material of the prism respectively are

(a)30°,$\sqrt{2}$

(b)45°,$\sqrt{2}$

(c)30°,$\frac{1}{\sqrt{2}}$

(d)45°,$\frac{1}{\sqrt{2}}$

The refracting angle of a prism is A, and refractive index of the material of the prism is cot(A/2). The angle of minimum deviation is-

In an astronomical telescope in normal adjustment a straight black line of length L is drawn on inside part of the objective lens. The eye-piece forms a real image of this line. The length of this image is l. The magnification of the telescope is:

If the focal length of the objective lens is increased, then magnifying power of :

The angle of a prism is A. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence 2A on the first surface returns back through the same path after suffering reflection at the silvered surface. The refractive index μ of the prism is