MCQs of Ray Optics & Optical Instruments

Ray Optics & Optical Instruments MCQs

MCQs of Ray Optics & Optical Instruments

Showing 91 to 100 out of 143 Questions

91.

If a ray of light strikes from a denser medium to a rarer medium at an angle of incidence i, the angle of reflection and refraction are respectively r and r'. If the reflected and refracted rays are at 90° to each other, the critical angle for the given pair of media is _____ .

(a)	sin^-1 (tan r')
(b)	cos^-1 (tan r')
(c)	sin^-1 (tan r)
(d)	cot^-1 (tan r)

92.

A ray of light passes through a prism having refractive index

\sqrt{2}

, suffers minimum deviation. If angle of incident is double the angle of refraction within prism, then angle of prism is _____ .

(a)	30°
(b)	45°
(c)	60°
(d)	90°

93.

A ray of light suffers minimum deviation when incident on a equilateral prism of refractive index

\sqrt{2}

. The angle of incidence is _____ .

(a)	45°
(b)	60°
(c)	90°
(d)	180°

94.

Light of certain colour has 2000 waves in a millimeter in air. What will be the wavelength of this light in medium of refractive index 1.25 ?

(a)	1000 $\overset{\circ}{A}$
(b)	2000 $\overset{\circ}{A}$
(c)	3000 $\overset{\circ}{A}$
(d)	4000 $\overset{\circ}{A}$

95.

A ray of light phases through an equilateral prism such that angle of incidence is equal to the angle of emergence and the later is equal to

\frac{3}{4}

th angle of prism. The angle of deviation is (δ_m) is _____ .

(a)	30°
(b)	40°
(c)	45°
(d)	50°

96.

A convex lens of glass (n = 1.5) has focal length of 20 cm. The lens is immersed in water of refractive index 1.33. The change in the power of convex lens is _____ .

(a)	1.86 D
(b)	3.72 D
(c)	4.62 D
(d)	6.44 D

97.

For a prism of refractive index

\sqrt{3}

, the angle of minimum deviation is equal to the angle of prism. The angle of the prism is _____ .

(a)	30°
(b)	40°
(c)	50°
(d)	60°

98.

A concave mirror has focal length 20 cm. The distance between the two positions of the object for which the image size is double of the object is _____ cm.

(a)	30
(b)	20
(c)	10
(d)	0

99.

A concave lens forms the image of an object such that the distance between the object and image is 10 cm and the magnification produced is

\frac{1}{4}

. The focal length of the lens will be _____ .

(a)	-6.2 cm
(b)	-12.4 cm
(c)	-4.4 cm
(d)	-8.8 cm

100.

One of the refracting surface of a prism of angle 30° is silvered. A ray of light incident at an angle of 60° retraces its path. The refractive index of the material of prism is _____ .

(a)	$\sqrt{3}$
(b)	$\frac{\sqrt{3}}{2}$
(c)	2
(d)	$\frac{3}{2}$

Showing 91 to 100 out of 143 Questions