MCQs of Ray Optics & Optical Instruments

Ray Optics & Optical Instruments MCQs

MCQs of Ray Optics & Optical Instruments

Showing 121 to 130 out of 143 Questions

121.

For which light critical angle is minimum ?

(a)	red
(b)	green
(c)	yellow
(d)	violet

122.

Total internal reflection ray of light by isosceles right angled prism experiences deviation by _____ .

(a)	360°
(b)	0°
(c)	180°
(d)	270°

123.

One concave and one convex lens have same focal length. If they are kept in contact, combination behaves as _____ .

(a)	Concave lens
(b)	Convex lens
(c)	Transparent plane plate
(d)	Curved surface

124.

A completely transparent body placed in vacuum remains invisible, so what will be its refractive index ?

(a)	one
(b)	more than one
(c)	less than one
(d)	1.33

125.

Focal length of convex lens for red, green and blue colour are f_r, f_g and f_b respectivley, so which of the following statements is true ?

(a)	f_r < f_g
(b)	f_g < f_r
(c)	f_b > f_r
(d)	f_r = f_g = f_b

126.

Image formed by concave refractive surface is _____ .

(a)	always real
(b)	always virtual
(c)	sometimes real and sometimes virtual.
(d)	no dependent on mode of formation of image.

127.

Focal length of lens is measured first in air and then in water. If these values are f₁ and f₂ then _____ .

(a)	f₁ = f₂
(b)	f₁ < f₂
(c)	f₁ > f₂
(d)	f₂ = 1.33 f₁

128.

An object lies on the principal axis of a concave mirror with radius of curvature 160 cm. Its vertical image appears at a distance 70 cm from it. Determine the position of the object and also the magnification.

(a)	-37 cm, -1.89
(b)	37 cm, 1.89
(c)	37 cm, -1.89
(d)	-37 cm, 1.89

129.

Derive the formula for lateral magnification,

m = \frac{f}{f - u}

for spherical mirrors; where f = focal length and u = object distance.

(a)	$\frac{f}{u - f}$
(b)	$\frac{f - u}{f}$
(c)	$\frac{f}{f - u}$
(d)	$\frac{f}{f + u}$

130.

A swimmer is diving in a swimming pool vertically down with a velocity of 2 ms^-1. What will be the velocity as seen by a stationery fish at the bottom of the pool, right below the diver ? Refractive index of water is 1.33.

(a)	2.66 cms^-1
(b)	26.6 cms^-1
(c)	266 cms^-1
(d)	26.6 ms^-1

Showing 121 to 130 out of 143 Questions