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Class 10 Science Chapter 9: Light: Reflection and Refraction MCQs with answers

10 multiple-choice questions on Light: Reflection and Refraction, each with its answer and the reason, written from the NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter.

Question 1
A ray of light strikes a plane mirror making an angle of 35° with the surface of the mirror. The angle of reflection is
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Answer: (b) 55°

Angles of incidence and reflection are measured from the normal. The ray makes 90° − 35° = 55° with the normal, so i = 55° and, since the angle of incidence equals the angle of reflection, r = 55°.

Question 2
Riya stands 1.2 m in front of a plane mirror fixed on a wall and then walks 0.4 m straight towards it. The distance between Riya and her image is now
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Answer: (c) 1.6 m

She is now 1.2 − 0.4 = 0.8 m from the mirror. A plane-mirror image is as far behind the mirror as the object is in front, so the image is 0.8 m behind it and the separation is 0.8 + 0.8 = 1.6 m.

Question 3
Kavya holds a concave mirror facing the Sun and finds the sharpest bright spot of sunlight on a card 14 cm in front of the mirror. The radius of curvature of the mirror is about
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Answer: (d) 28 cm

The bright spot is the real image of the distant Sun, formed at the principal focus, so f ≈ 14 cm. For a mirror of small aperture R = 2f = 28 cm.

Question 4
Of the pole P, the principal focus F and the centre of curvature C of a concave mirror, the point that lies on the reflecting surface itself is
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Answer: (a) P only

The pole is the centre of the reflecting surface and lies on the mirror. F and C lie on the principal axis in front of a concave mirror, not on its surface.

Question 5
A beam of light parallel to the principal axis falls on the convex mirror of a shop's security mirror. After reflection the rays
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Answer: (d) appear to diverge from a point on the principal axis behind the mirror

A convex mirror reflects parallel rays so that they appear to come from a point on the principal axis behind the mirror; that point is its principal focus.

Question 6
A small bulb is placed 35 cm in front of a concave mirror of focal length 10 cm. The image of the bulb is formed
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Answer: (b) between F and C; diminished, real and inverted

C is at 2f = 20 cm, so the bulb at 35 cm is beyond C. With the object beyond C a concave mirror forms the image between F and C: diminished, real and inverted.

Question 7
A dentist holds a small concave mirror close to a patient's tooth, nearer to the tooth than the mirror's focal length. The mirror is used this way because the image of the tooth is then
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Answer: (d) virtual, erect and enlarged

With the object between the pole and the focus, a concave mirror forms an enlarged, virtual and erect image behind the mirror; that is why dentists use it to see large images of teeth.

Question 8
Meenal wants to see the complete image of a tall building behind her in a small hand mirror. She should use
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Answer: (d) a convex mirror

A convex mirror always forms an erect, diminished image, so a small one can show a full-length image of a large object such as a tall building; a plane or concave mirror of the same size cannot.

Question 9
A ray of light is directed towards the centre of curvature of a convex mirror. After reflection the ray
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Answer: (c) is reflected back along the same path

A ray directed towards the centre of curvature strikes the mirror along the normal, so it is reflected straight back along the same path.

Question 10
A ray of light strikes the pole of a concave mirror making an angle of 25° with the principal axis. The angle between the incident ray and the reflected ray is
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Answer: (b) 50°

At the pole the principal axis is the normal. The reflected ray makes 25° with the axis on the other side, so the angle between the two rays is 25° + 25° = 50°.

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