Ray Optics & Optical Instruments  MCQs

MCQs of Ray Optics & Optical Instruments

Showing 111 to 120 out of 143 Questions
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111.
The radii of curvature of both the sides of a convex lens are 15 cm and if the refractive index of the material of the lens is 1.5, then focal length of lens in air is _____ cm.
(a) 10
(b) 15
(c) 20
(d) 30
Answer:

Option (b)

112.
An image of an object obtained by a convex mirror is n times smaller than the object. If the focal length of lens is f, the object distance would be _____ .
(a) fn
(b) f(n - 1)
(c) (n - 1)f
(d) nf
Answer:

Option (c)

113.
An air bubble in a glass slab with refractive index 1.5 is 5 cm deep when viewed from one face and 2 cm deep when viewed from the opposite face. The thickness of the slab is _____ cm.
(a) 10.5
(b) 7
(c) 105
(d) 70
Answer:

Option (a)

114.
Time taken by the sunlight to pass through a slab of thickness 4 mm and refractive index 1.5 is _____ sec.
(a) 2 x 10-8
(b) 2 x 108
(c) 2 x 10-11
(d) 2 x 1011
Answer:

Option (c)

115.
The top sky looks blue in morning hours because, _____
(a) red light is absorbed
(b) blue light is scattered the most
(c) sun radiates blue light only in the morning.
(d) blue light is absorbed by the sky
Answer:

Option (b)

116.
A defect of vision in which lines in one plane of an object appear in focus while those in another plane are out of focus is called _____ .
(a) astigmatism
(b) distortion
(c) myopia
(d) hypermetropia
Answer:

Option (a)

117.
A spherical convex surface separates an object and image spaces of refractive index 1.0 and 1.5 respectively. If radius of curvature of the surface is 25 cm, its power is _____ D.
(a) 13
(b) 33
(c) 3.3
(d) 1.3
Answer:

Option (d)

118.
A light ray is incident at an angle 30° with normal on a 3 cm thick plane slab of refractive index n = 2.0. The lateral shift of the incident ray is _____ cm.
(a) 0.835
(b) 8.35
(c) 1.5
(d) 1.197
Answer:

Option (a)

119.
If _____ relation R = 2f is true for spherical mirror.
(a) aperture of mirror is big.
(b) aperture of mirror is small.
(c) it is only curved mirror.
(d) incident paraxial rays are parallel to axis.
Answer:

Option (b)

120.
When ray of light moves from air to glass slab _____ .
(a) Its wavelength decreases.
(b) Its wavelength increases.
(c) Its frequency increases.
(d) Wavelength or frequency does not change.
Answer:

Option (a)

Showing 111 to 120 out of 143 Questions
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