OPTICS

The refractive index of four substances A, B,

C and D are 1.31, 1.43, 1.33, 2.4 respectively.

The speed of light is maximum in

• A

• B

• C

• D

Where should an object be placed so that

a real and inverted image of same size is

obtained by a convex lens

• f

• 2f

• infinity

• between f and 2f

A small bulb is placed at the principal focus

of a convex lens. When the bulb is switched

on, the lens will produce

• a convergent beam of light

• a divergent beam of light

• a parallel beam of light

• a coloured beam of light

Magnification of a convex lens is

• Positive

• b) negative

• either positive or negative

• zero

A convex lens forms a real, diminished point

sized image at focus. Then the position of the

object is at

• focus

• infinity

• at 2f

• between f and 2f

Power of a lens is –4D, then its focal length is

• 4m

• –40m

• –0.25 m

• –2.5 m

In a myopic eye, the image of the object is

formed

• behind the retina

• on the retina

• in front of the retina

• on the blind spot

The eye defect ‘presbyopia’ can be corrected

by

• convex lens

• concave lens

• convex mirror

• Bi focal lenses

Which of the following lens would you prefer

to use while reading small letters found in a

dictionary?

• A convex lens of focal length 5 cm

• A concave lens of focal length 5 cm

• A convex lens of focal length 10 cm

• A concave lens of focal length 10 cm

If VB, VG, VR be the velocity of blue, green

and red light respectively in a glass prism,

then which of the following statement gives

the correct relation?

• V_B = V_G = V_R

• V_B > V_G >V_R

• V_B < V_G < V_R

• V_B < V_G > V_R