Light MCQ question and answer with solution

61

When a person enters into a dark room from the strong light area, he is not able to see clearly for some time. Later he gradually begins to see things. This is because

A) Changes in the size of pupil B) Changes in the diameter and focal length of lens C) Bleaching and reformation of Rhodopsins D) Eyes become familiar with darkness in course of time

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Answer & Solution

Answer: Option D

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62

The point at which all the rays meet is called . . . . . . . .

A) aperture B) main axis C) pole D) focus

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Answer & Solution

Answer: Option D

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63

For a ray of light to suffer total internal reflection, it has to pass from

A) glass to water B) water to glass C) air to water D) air to glass

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Answer & Solution

Answer: Option C

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64

A person is unable to read a newspaper without his glasses. He is most probably suffering from

A) myopia B) presbyopia C) astigmatism D) hypermetropia

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Answer & Solution

Answer: Option B

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65

What is the principal focus of a spherical mirror?

A) It is a point from which the rays of light appear to be coming from on the principal axis of a convex mirror B) It is the point on the principal axis through which rays of light parallel to the principal axis pass after reflection on appear to be arising from this point on the principal axis C) It is the centre of a hollow sphere of which the spherical mirror is a part D) It is the midpoint of a spherical mirror

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Answer & Solution

Answer: Option B

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66

A spherical mirror and a thin spherical lens each have a focal length of -20 cm. Which of the following is likely to be true in such a scenario?

A) Both are convex B) The mirror is concave and the lens is convex C) The mirror is convex and the lens is concave D) Both are concave

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Answer & Solution

Answer: Option D

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67

When the sun is near the horizon during the morning or evening, it appears reddish. The phenomenon that is responsible for this observation is

A) reflection of light B) refraction of light C) dispersion of light D) scattering of light

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Answer & Solution

Answer: Option D

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68

In case of reflection, it is well known that, when a mirror turned through an angle the reflected ray turns through

A) same angle B) twice the angle C) thrice the angle D) half the angle

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Answer & Solution

Answer: Option A

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69

When light enters the denser medium through rarer medium, it is slow and . . . . . . . .

A) is reflected in a medium of low density B) bends away from normal C) there is no change in it D) bends towards normal

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Answer & Solution

Answer: Option D

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70

The speed of light in vacuum is estimated to be . . . . . . . . m/s.

A) 3.00 × 10⁸ B) 3.10 × 10⁸ C) 3.12 × 10⁸ D) 3.15 × 10⁸

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Answer & Solution

Answer: Option A

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Light MCQ question and answer with solution | Physics Gk MCQs