Class 8 Science Curiosity Chapter 10 Solutions (NCERT 2026–27) – Light: Mirrors and Lenses

These Class 8 Science Curiosity Chapter 10 solutions cover Light: Mirrors and Lenses from the new NCF-2023 textbook (2026–27), with every “Keep the curiosity alive” question solved step by step.

Class: 8 Subject: Science Book: Curiosity Chapter: 10 Exercise: Keep the curiosity alive (12 Qs) Session: 2026–27
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Class 8 Science Curiosity Chapter 10 Solutions – Overview

Chapter 10 of Curiosity, Light: Mirrors and Lenses, moves beyond the plane mirror to spherical mirrors (concave and convex) and lenses (convex and concave). It explains how a concave mirror can give an enlarged or inverted image while a convex mirror always gives an erect, diminished image, and where each is used (torch reflectors, dental mirrors, side-view and road-safety mirrors). It states the two laws of reflection, shows how concave mirrors converge and convex mirrors diverge light, and introduces convex (converging) and concave (diverging) lenses with everyday examples like magnifying glasses, cameras, eyeglasses and the eye. These Class 8 Science Curiosity Chapter 10 solutions answer every textbook question step by step.

Key Concepts & Definitions

Spherical mirror: a mirror whose reflecting surface is part of a hollow sphere. A concave mirror curves inwards; a convex mirror curves outwards.

Concave mirror image: can be enlarged, diminished or same size, and erect or inverted, depending on the object distance (erect & enlarged when close, inverted when far). Convex mirror image: always erect and diminished.

Laws of reflection: (1) the angle of incidence (i) equals the angle of reflection (r); (2) the incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane. They hold for plane and spherical mirrors.

Normal: the line drawn at 90° to the mirror at the point of incidence. Angle of incidence (i): between incident ray and normal. Angle of reflection (r): between reflected ray and normal.

Converge / diverge: a concave mirror and a convex lens converge a parallel beam; a convex mirror and a concave lens diverge it.

Lens: a transparent material with curved surfaces. A convex lens is thicker in the middle (converging); a concave lens is thicker at the edges (diverging). We see things through a lens, not in it.

“Probe and Ponder” & In-text Questions — Answers

Can we make mirrors which can give enlarged or diminished images?

ANSWERYes. A concave mirror can give an enlarged image (when the object is close, as in a dental mirror), and a convex mirror always gives a diminished image. These are spherical mirrors with curved reflecting surfaces.

On side-view mirrors of vehicles, there is a warning that says “Objects in mirror are closer than they appear”. Why is this warning written there?

ANSWERSide-view mirrors are convex mirrors. They always form a diminished (smaller) erect image and cover a wider area of the road behind. Because the vehicle behind looks smaller, the brain judges it to be farther away than it really is, so the warning reminds the driver that the object is actually closer.

Why is there a curved line on some reading glasses?

ANSWERReading glasses are lenses with curved surfaces. The faint curved line is the edge of the curved (often convex) lens surface, which bends light and makes small print appear larger and clearer for the reader.

(Activity 10.1) When you hold the inner and outer curved surfaces of a shiny metallic spoon close to your face, how do the two images differ?

ANSWERThe inner (concave) surface gives an image that is inverted (when held a little away), behaving like a concave mirror. The outer (convex) surface gives an image that is erect but smaller, behaving like a convex mirror.

(Activity 10.3) When an object is placed in front of concave and convex mirrors and slowly moved away, what changes are seen in the images?

ANSWERIn a concave mirror, when the object is close the image is erect and enlarged; as it moves away the image becomes inverted and keeps getting smaller. In a convex mirror, the image is always erect and diminished, shrinking slightly as the object moves away. Lateral inversion is seen in all mirrors.

(Activity 10.6) What happens when multiple parallel beams of light fall on plane, concave and convex mirrors?

ANSWERFrom a plane mirror the reflected beams stay parallel; from a concave mirror they converge (come closer); from a convex mirror they diverge (spread apart). Each ray still obeys the laws of reflection.

Class 8 Science Curiosity Chapter 10 Solutions — Keep the Curiosity Alive

1. A light ray is incident on a mirror and gets reflected by it (Fig. 10.21). The angle made by the incident ray with the normal to the mirror is 40°. What is the angle made by the reflected ray with the mirror? (i) 40°   (ii) 50°   (iii) 45°   (iv) 60°

ANSWER (ii) 50°. By the law of reflection the angle of reflection equals the angle of incidence = 40° (measured from the normal). The angle with the mirror = 90° − 40° = 50°.

2. Fig. 10.22 shows three different situations where a light ray falls on a mirror: (i) The light ray falls along the normal. (ii) The mirror is tilted, but the light ray still falls along the normal to the tilted surface. (iii) The mirror is tilted, and the light ray falls at an angle of 20° from the normal. Draw the reflected ray in each case (Use a ruler and protractor for accurate drawing). What is the angle of reflection in each case?

ANSWER (i) The ray falls along the normal, so i = 0°; the reflected ray travels straight back along the same line. Angle of reflection = 0°. (ii) The ray again strikes along the normal of the tilted mirror, so i = 0° and it is reflected straight back. Angle of reflection = 0°. (iii) The ray makes 20° with the normal, so by the law of reflection the reflected ray makes 20° on the other side of the normal. Angle of reflection = 20°.

3. In Fig. 10.23, the cap of a sketch pen is placed in front of three types of mirrors. Match each image with the correct mirror.

ANSWER
ImageMirror
(i) Smaller, erect imageConvex mirror
(ii) Larger, erect (enlarged) imageConcave mirror
(iii) Same-size, erect imagePlane mirror
A convex mirror always diminishes, a concave mirror (object close) enlarges, and a plane mirror keeps the same size — so the diminished image is the convex mirror, the enlarged one the concave mirror, and the same-size one the plane mirror.

4. In Fig. 10.24, the cap of a sketch pen is placed behind a convex lens, a concave lens, and a flat transparent glass piece — all at the same distance. Match each image with the correct type of lens or glass.

ANSWER
ImageLens/glass type
(i) Larger (enlarged), erect imageConvex lens
(ii) Smaller (diminished), erect imageConcave lens
(iii) Same-size imageFlat transparent glass piece
A convex lens (object close) makes the cap look enlarged, a concave lens always makes it diminished, and a flat glass piece does not change its size.

5. When the light is incident along the normal on the mirror, which of the following statements is true: (i) Angle of incidence is 90° (ii) Angle of incidence is 0° (iii) Angle of reflection is 90° (iv) No reflection of light takes place in this case

ANSWER (ii) Angle of incidence is 0°. The angle of incidence is measured from the normal; when the ray travels along the normal it makes 0° with it, so both the angle of incidence and the angle of reflection are 0° and the light is reflected straight back.

6. Three mirrors—plane, concave and convex are placed in Fig. 10.25. On the basis of the images of the graph sheet formed in the mirrors, identify the mirrors and write their names above the mirrors.

ANSWER Compare the image of the graph-sheet squares with the real squares: • The mirror whose squares look the same size as the real grid is the plane mirror. • The mirror whose squares look larger / magnified (and may curve outward) is the concave mirror. • The mirror whose squares look smaller, packing more of the grid into a small area, is the convex mirror.

7. In a museum, a woman walks towards a large concave mirror (Fig. 10.26). She will see that: (i) her erect image keeps decreasing in size. (ii) her inverted image keeps decreasing in size. (iii) her inverted image keeps increasing in size and eventually it becomes erect and magnified. (iv) her erect image keeps increasing in size.

ANSWER (iii). When she is far from the concave mirror the image is inverted. As she walks closer the inverted image first grows larger, and once she is very close the image becomes erect and magnified — matching what is observed with a dental mirror held close to the teeth.

8. Hold a magnifying glass over text and identify the distance where you can see the text bigger than they are written. Now move it away from the text. What do you notice? Which type of lens is a magnifying glass?

ANSWER When the magnifying glass is held close to the text, the letters appear enlarged and erect. As it is moved farther away, the letters first appear bigger and blurred and then become inverted and smaller. A magnifying glass is a convex lens (converging lens).

9. Match the entries in Column I with those in Column II.

ANSWER
Column IColumn II
(i) Concave mirror(a) Spherical mirror with a reflecting surface that curves inwards.
(ii) Convex mirror(b) It forms an image which is always erect and diminished in size.
(iii) Convex lens(c) Object placed behind it may appear inverted at some distance.
(iv) Concave lens(d) Object placed behind it always appears diminished in size.
Matches: (i)→(a), (ii)→(b), (iii)→(c), (iv)→(d).

10. The following question is based on Assertion/Reason. Assertion: Convex mirrors are preferred for observing the traffic behind us. Reason: Convex mirrors provide a significantly larger view area than plane mirrors. Choose the correct option: (i) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. (ii) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion. (iii) Assertion is correct but Reason is incorrect. (iv) Both Assertion and Reason are incorrect.

ANSWER (i). Both statements are true, and the Reason correctly explains the Assertion: because a convex mirror curves outward it covers a much wider area of the road behind, which is exactly why it is preferred for observing traffic.

11. In Fig. 10.27, note that O stands for object, M for mirror, and I for image. Which of the following statements is true? (i) Figure (a) indicates a plane mirror and Figure (b) indicates a concave mirror. (ii) Figure (a) indicates a convex mirror and Figure (b) indicates a concave mirror. (iii) Figure (a) indicates a concave mirror and Figure (b) indicates a convex mirror. (iv) Figure (a) indicates a plane mirror and Figure (b) indicates a convex mirror.

ANSWER (iv). In figure (a) the image I is the same size as the object O → plane mirror. In figure (b) the image I is smaller (diminished) than O → convex mirror.

12. Place a pencil behind a transparent glass tumbler (Fig. 10.28a). Now fill the tumbler halfway with water (Fig. 10.28b). How does the pencil appear when viewed through the water? Explain why its shape appears changed.

ANSWER The part of the pencil seen through the water looks thicker, shifted and even bent or broken at the water level, while the part above water looks normal. Reason: the round water-filled tumbler acts like a convex lens. Light from the pencil refracts (bends) as it passes from water/glass into air, so the magnified, displaced part no longer lines up with the part above the water — making the pencil appear changed in shape and size.

Common Misconceptions to Avoid

Watch out for these

  • Measuring the angle of incidence/reflection from the mirror surface — both angles are always measured from the normal.
  • Thinking a concave mirror only enlarges — it enlarges when the object is close, but gives an inverted, smaller image when the object is far.
  • Believing a convex mirror can magnify — it always gives an erect, diminished image.
  • Mixing up the shapes: a convex lens is thicker in the middle (converging); a concave lens is thicker at the edges (diverging).
  • Confusing converging behaviour — concave mirror & convex lens converge; convex mirror & concave lens diverge.
  • Saying we see an image “in” a lens — with lenses we see things through the lens (light passes through), unlike mirrors.

Extra Practice Questions

Very Short Answer Type Questions

Q1. Which type of spherical mirror always forms an erect and diminished image?

ANSWERA convex mirror.

Q2. What is the line drawn at 90° to a mirror at the point of incidence called?

ANSWERThe normal.

Q3. Name the lens used as a magnifying glass.

ANSWERA convex (converging) lens.

Short Answer Type Questions

Q1. State the two laws of reflection.

ANSWER(1) The angle of incidence is equal to the angle of reflection. (2) The incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane.

Q2. Why are convex mirrors used as side-view mirrors in vehicles?

ANSWERA convex mirror always forms an erect, diminished image and covers a wider field of view, so the driver can see a larger area of the traffic behind in a small mirror.

Long Answer Type Question

Q1. Compare the images formed by a concave mirror and a convex mirror as the object is moved from close to far, and give one practical use of each.

ANSWER Concave mirror: when the object is close, the image is erect and enlarged; as the object moves away the image becomes inverted and gradually smaller. The image can therefore be enlarged, diminished or same-size and erect or inverted. Use: dentist’s mirror, torch and headlight reflectors, reflecting telescopes, solar concentrators. Convex mirror: the image is always erect and diminished, shrinking slightly as the object moves away, and it covers a wide area. Use: vehicle side-view mirrors, road-safety mirrors at bends, surveillance mirrors in shops.

MCQs & Assertion–Reason

1. A mirror whose reflecting surface curves inwards is a:

(a) plane mirror    (b) concave mirror    (c) convex mirror    (d) glass slab

2. A convex mirror always forms an image that is:

(a) erect and diminished    (b) inverted and enlarged    (c) erect and enlarged    (d) same size as object

3. The angle of incidence is always measured from the:

(a) mirror surface    (b) reflected ray    (c) normal    (d) object

4. If the angle of incidence is 35°, the angle of reflection is:

(a) 0°    (b) 35°    (c) 55°    (d) 90°

5. A parallel beam of light is converged by a:

(a) convex mirror    (b) concave mirror    (c) plane mirror    (d) concave lens

6. A lens that is thicker at the middle than at the edges is a:

(a) concave lens    (b) convex lens    (c) plane mirror    (d) glass slab

7. A concave lens is also called a:

(a) converging lens    (b) diverging lens    (c) magnifying lens    (d) plane lens

8. The mirror used by a dentist to get an enlarged view of teeth is a:

(a) convex mirror    (b) plane mirror    (c) concave mirror    (d) concave lens

9. When light falls along the normal on a mirror, the angle of reflection is:

(a) 0°    (b) 45°    (c) 90°    (d) 180°

10. A convex lens used to concentrate sunlight onto paper can make it burn because it:

(a) diverges the light    (b) converges the light to a point    (c) absorbs the light    (d) reflects the light

Answer key: 1-(b), 2-(a), 3-(c), 4-(b), 5-(b), 6-(b), 7-(b), 8-(c), 9-(a), 10-(b).

For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.

A-R 1. Assertion: A convex mirror is used as a side-view mirror in vehicles.

Reason: A convex mirror gives a wide, erect and diminished view of the traffic behind.

A-R 2. Assertion: A concave mirror can form an enlarged image.

Reason: When the object is placed close to a concave mirror, the image is erect and magnified.

A-R 3. Assertion: A convex lens is called a diverging lens.

Reason: A convex lens spreads out a parallel beam of light passing through it.

A-R 4. Assertion: The angle of incidence equals the angle of reflection.

Reason: The incident ray, the normal and the reflected ray do not lie in the same plane.

A-R 5. Assertion: A pencil seen through a water-filled glass tumbler appears bent and thicker.

Reason: Light refracts as it passes from water and glass into air, and the tumbler acts like a convex lens.

Answer key: 1-(A), 2-(A), 3-(D), 4-(C), 5-(A).

Quick Revision Summary

  • Image formed by a concave mirror can be enlarged, diminished or of the same size, and erect or inverted, depending on the object distance.
  • Image formed by a convex mirror is always erect and diminished in size.
  • Two laws of reflection: (i) angle of incidence = angle of reflection; (ii) the incident ray, normal and reflected ray lie in the same plane.
  • The laws of reflection hold for all mirrors — plane, concave and convex.
  • A concave mirror converges a light beam; a convex mirror diverges it.
  • Image formed by a convex lens can be enlarged, diminished or same size, and erect or inverted; a concave lens always gives an erect, diminished image.
  • A convex lens converges light (converging lens); a concave lens diverges it (diverging lens).

Real-life Applications

Spherical mirrors and lenses are all around us. Concave mirrors form the reflectors of torches, car and scooter headlights, dentists’ mirrors, reflecting telescopes and solar concentrators (even solar cookers and solar furnaces hot enough to melt steel). Convex mirrors serve as vehicle side-view mirrors, road-safety mirrors at sharp bends, and surveillance mirrors in shops. Lenses are used in magnifying glasses, eyeglasses, cameras, telescopes and microscopes — and our own eye contains a flexible convex lens that lets us focus on near and far objects.

How to score full marks in this chapter

Always measure i and r from the normal, not the mirror, and remember i = r. Memorise the fixed rule — convex mirror and concave lens always give erect, diminished images. For the concave mirror and convex lens, link the image to object distance (close = erect/enlarged, far = inverted). For “identify the mirror/lens” questions, compare the image size to the object: same = plane/glass, bigger = concave mirror/convex lens, smaller = convex mirror/concave lens.

Frequently Asked Questions

What is Class 8 Science Curiosity Chapter 10 about?

Chapter 10, Light: Mirrors and Lenses, covers spherical mirrors (concave and convex), the laws of reflection, how mirrors converge or diverge light, and convex and concave lenses, along with their everyday uses.

What is the difference between a concave and a convex mirror?

A concave mirror curves inwards and can form enlarged, diminished, erect or inverted images depending on the object distance; a convex mirror curves outwards and always forms an erect, diminished image with a wide field of view.

How many questions are in the “Keep the curiosity alive” exercise of Chapter 10?

There are 12 questions, all solved on this page along with the “Probe and ponder” and in-text activity questions.

Are these Class 8 Science Curiosity Chapter 10 solutions free?

Yes. All solutions are free and follow the official NCERT Curiosity textbook for 2026–27.

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