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

(a) 1.04°                     (b) 5°

(c) 0.96°                      (d) 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 :

(a) Are parallel to each other

(b) Are diverging

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

(d) 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 

(a) ${\sin }^{-1}\left(\frac{1}{\mu }\right)$                             (b) ${\tan }^{-1}\left(\frac{1}{\mu }\right)$

(c) ${\sin }^{-1}\left(\frac{\mu -1}{\mu }\right)$                         (d) ${\cos }^{-1}\left(\frac{1}{\mu }\right)$

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 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?
           

(1) 5cm/sec towards the mirror

(2) 4cm/sec towards the mirror

(3) 4cm/sec away from the mirror

(4) 9cm/sec away from the mirror

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

(a) v                                            (b) 2v

(c) 2v cos $\theta$                                    (d) 2v sin $\theta$

A thin prism having refracting angle ${10}^{°}$ is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should be 

(a)$4^{°}$

(b)$6^{°}$

(c)$8^{°}$

(d)${10}^{°}$