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)

A

(b)

B

(c)

C

(d)

D

A small bulb is placed at the principal focus of a convex lens. When the bulb is switched on, the lens will produce

(a)

a convergent beam of light

(b)

a divergent beam of light

(c)

a parallel beam of light

(d)

a coloured beam of light

A convex lens forms a real, diminished point sized image at focus. Then the position of the object is at

(a)

focus

(b)

infinity

(c)

at 2f

(d)

between f and 2f

In a myopic eye, the image of the object is formed

(a)

behind the retina

(b)

on the retina

(c)

in front of the retina

(d)

on the blind spot

Which of the following lens would you prefer to use while reading small letters found in a dictionary?

(a)

A convex lens of focal length 5 cm

(b)

A concave lens of focal length 5 cm

(c)

A convex lens of focal length 10 cm

(d)

A concave lens of focal length 10 cm