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.

1. 1.25 cm                             

2. 2.5 cm

3. 1.05 cm                             

4. 2 cm

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

1. 1.04°                     

2. 5°

3. 0.96°                     

4. 13.5°

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 :

1. Are parallel to each other

2. Are diverging

3. Make an angle $2{\sin }^{-1}\left(0.72\right)$ with each other

4. Make an angle $2\left\{{\sin }^{-1}\left(0.72\right)-30°\right\}$ with each other

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 

1. ${\sin }^{-1}\left(\frac{1}{\mu }\right)$                            

2. ${\tan }^{-1}\left(\frac{1}{\mu }\right)$

3. ${\sin }^{-1}\left(\frac{\mu -1}{\mu }\right)$                        

4. ${\cos }^{-1}\left(\frac{1}{\mu }\right)$

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 

1. 3.0                               

2. 2.0

3. 2.5                               

4. 1.5

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

1. $\left(\frac{\mathrm{\pi }}{2}-C\right)$                         

2. 2C

3. $\mathrm{\pi }-2\mathrm{C}$                             

4. $\mathrm{\pi }-\mathrm{C}$

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

1. 10 $cm{s}^{-1}$                           

2. 20 $cm{s}^{-1}$

3. $\frac{10}{\sqrt{2}}cm{s}^{-1}$                          

4. $10\sqrt{2}cm{s}^{-1}$

Figure shows a cubical room ABCD with the wall CD as a plane mirror. Each side of the

room is 3m. We place a camera at the midpoint of the wall AB. At what distance should

the camera be focussed to photograph an object placed at A

1. 1.5 m                                     

2. 3 m

3. 6 m                                         

4. More than 6 m

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

1. v                                           

2. 2v

3. 2v cos $\theta$                                    

4. 2v sin $\theta$