Ray Optics & Optical Instruments  MCQs

MCQs of Ray Optics & Optical Instruments

Showing 31 to 40 out of 143 Questions
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31.
An object is placed at a distance of 40 cm in front of a concave mirror of focal length 20 cm. The image produced is _____ .
(a) real and erect
(b) virtual and inverted
(c) real, inverted and smaller in size
(d) real, inverted and of same size
Answer:

Option (d)

32.
A wavelength of a monochromatic light in vacuum is λ. It travels from vacuum to a medium of absolute refractive index μ. The ratio of wavelength of the incident and refracted wave is _____ .
(a) μ : 1
(b) 1 : μ
(c) μ2 : 1
(d) 1 : 1
Answer:

Option (a)

33.
A real object is placed at a distance f from the pole of a convex mirror, in front of the convex mirror. If focal length of the mirror is f, then distance of the image from the pole of the mirror is _____ .
(a) 4f
(b) 2f
(c) f4
(d) f2
Answer:

Option (d)

34.
An astronomical telescope has objective and eye-piece lenses of powers 0.5 D and 20 D respectively. What will be its magnifying power ?
(a) 40
(b) 30
(c) 20
(d) 10
Answer:

Option (a)

35.
The magnifying power of a telescope is 'm'. If the focal length of its eye lens is halved, the magnifying power will become _____ .
(a) 2 m
(b) 3 m
(c) 4 m
(d) 5 m
Answer:

Option (a)

36.
Where should a person stand straight from the pole of a convex mirror of focal length 2.0 m on its axis so that the image formed become half of its original height ?
(a) -2.60 m
(b) -4.0 m
(c) -0.5 m
(d) -2.0 m
Answer:

Option (d)

37.
Refractive index of the material of a prism is 1.5. If δm = A, what will be a value of angle of the given prism ? (where δm = minimum deviation; A = angle of prism)
(a) 82.8°
(b) 41.4°
(c) 48.6°
(d) 90°
Answer:

Option (a)

38.
A microscope is focused on an ink mark on the top of a table. If we place a glass slab of 3 cm thick on it, how should the microscope be moved to focus the ink spot again ? The refractive index of glass is 1.5.
(a) 2 cm upwards
(b) 2 cm downwards
(c) 1 cm upwards
(d) 1 cm downwards
Answer:

Option (c)

39.
The refractive index of water with respect to air is 43. The refractive index of glass with respect to air is 32. What is the refractive index of glass with respect to water ?
(a) 12
(b) 89
(c) 2
(d) 98
Answer:

Option (d)

40.
Prism angle of a prism is A. It is made up of material of refractive index cot A2. What is the angle of minimum deviation of prism ?
(a) 180 - 4A
(b) 180 - 2A
(c) 180 - 3A
(d) 180 - A
Answer:

Option (b)

Showing 31 to 40 out of 143 Questions
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