NCERT Solutions for Class 7 Science (Curiosity) Chapter 11: Light: Shadows and Reflections (NCERT 2026–27)

These Class 7 Science Curiosity Chapter 11 solutions cover Light: Shadows and Reflections from the new NCF-2023 textbook (2026–27). The chapter explains why light is so special: it travels in straight lines through a uniform medium, until it meets a boundary or obstacle. From this single idea grow shadows, reflection in a mirror, the upside-down image of a pinhole camera, and clever devices like the periscope and kaleidoscope. Every textbook question from Let Us Enhance Our Learning is reproduced verbatim below and answered in clear, exam-ready steps.

Class: 7 Subject: Science Book: Curiosity Chapter: 11 Topic: Light, Shadows & Reflection Session: 2026–27
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Class 7 Science Curiosity Chapter 11 Solutions – Overview

Chapter 11 of Curiosity, Light: Shadows and Reflections, begins with the difference between luminous objects (which emit their own light, like the Sun, stars and fireflies) and non-luminous objects (like the Moon, which only reflect light). The chapter then establishes its central idea through simple activities — the matchbox holes and the bent pipe — that light travels in a straight line. Because of this, opaque objects block light to form shadows, while transparent materials let light pass and translucent ones pass it partly. A shiny surface or mirror changes the direction of light, which is called reflection. A plane mirror forms an image that is erect, the same size as the object, laterally inverted, and cannot be caught on a screen. The straight-line nature of light also explains the inverted image of a pinhole camera, and reflection is used to build a periscope and a kaleidoscope.

Key Concepts & Definitions

Luminous object: an object that emits its own light, such as the Sun, stars, lightning, fire and certain animals (fireflies).

Non-luminous object: an object that does not emit its own light and is seen only because it reflects light, e.g. the Moon.

Rectilinear propagation of light: light travels in a straight line. This is shown by the matchbox-hole activity and by being unable to see a candle flame through a bent pipe.

Transparent, translucent, opaque: light passes almost completely through transparent materials, partially through translucent materials, and not at all through opaque materials.

Shadow: the dark patch formed when an opaque object blocks the straight path of light. We need a source of light, an opaque object and a screen to see a shadow. Changing the colour of the object does not change the colour of the shadow.

Reflection of light: light returning from a surface. Smooth surfaces give regular reflection; rough surfaces also reflect light, but in many directions.

Image in a plane mirror: erect, the same size as the object, laterally inverted (left–right reversed), and cannot be obtained on a screen (a virtual image).

Lateral inversion: the apparent left–right reversal in a mirror image — your left hand appears as the right hand of the image.

Pinhole camera: a device in which light from an object passes through a tiny hole to form an inverted (upside-down) image on a screen.

Periscope & kaleidoscope: useful devices made using two and three plane mirrors respectively, working on the reflection of light.

Let Us Enhance Our Learning – NCERT Solutions

All questions below are reproduced verbatim from the NCERT Curiosity (Class 7) end-of-chapter exercise “Let Us Enhance Our Learning”. Answers are original and exam-ready.

1. Which of the following are luminous objects?Mars, Moon, Pole Star, Sun, Venus, Mirror

ANSWER Luminous objects emit their own light. Out of the given objects, only the Sun and the Pole Star are luminous, because the Sun and all stars produce their own light. Mars, the Moon, Venus and a mirror are non-luminous — they do not make their own light; the planets and Moon reflect sunlight; a mirror reflects light from whatever source illuminates it.

2. Match the items in Column A with those in Column B.

ANSWER
Column AColumn B (correct match)
Pinhole cameraForms an inverted image
Opaque objectBlocks light completely
Transparent objectLight passes almost completely through it
ShadowThe dark region formed behind the object

3. Sahil, Rekha, Patrick, and Qasima are trying to observe the candle flame through the pipe as shown in Fig. 11.16. Who can see the flame?

ANSWER Light travels in a straight line, so a person can see the candle flame only if the pipe is straight and lined up directly with the flame and the eye. In Fig. 11.16, only the person whose pipe forms a straight, unbroken line from the eye to the flame can see it — that is Rekha, who holds the straight pipe aimed at the flame. The others use bent pipes (or pipes not aligned with the flame), so the light is blocked and they cannot see the flame. Reasoning to write in the exam: a bent pipe interrupts the straight-line path of light, so no light from the flame reaches the eye.

4. Look at the images shown in Fig. 11.17 and select the correct image showing the shadow formation of the boy.

ANSWEROption (d) is correct. The Sun is towards the upper right of the boy and the shadow extends away from it, towards the lower left on the ground. It is a dark silhouette, not a coloured copy of the boy.

5. The shadow of a ball is formed on a wall by placing the ball in front of a fixed torch as shown in Fig. 11.18. In scenario (i) the ball is closer to the torch, while in scenario (ii) the ball is closer to the wall. Choose the most accurate representation of the shadows formed in both scenarios from the options provided (a and b).

ANSWERScenario (i) → (b); scenario (ii) → (a), comparing the larger and smaller shadow outlines in the printed options. With the torch and wall fixed, a ball nearer the torch blocks a wider cone of light and gives a larger shadow. Moving it nearer the wall reduces the shadow size. The printed sketches are schematic; judge the relative size rather than treating the drawn blur as a measurement.

6. Based on Fig. 11.18, match the position of the torch in Column A with the characteristics of the ball’s shadow in Column B.

ANSWER
Column AColumn B (correct match)
If the torch is close to the ballThe shadow would be larger
If the torch is far awayThe shadow would be smaller
If the ball is removed from the set-upA bright spot would appear on the screen
If two torches are present in the set-up on the left side of the ballTwo shadows would appear on the screen
Why: the closer the light is to the object, the more the light spreads out and the bigger the shadow; with no object, light reaches the screen freely as a bright spot; each separate light source casts its own shadow.

7. Suppose you view the tree shown in Fig. 11.19 through a pinhole camera. Sketch the outline of the image of the tree formed in the pinhole camera.

ANSWERDraw the tree upside down: the crown is below and the base of the trunk is above. Rays from opposite ends cross at the pinhole. The image is rotated through 180° in its plane, so left and right features are reversed as well. Its size depends on the object and screen distances; it need not equal the tree’s actual size.
Rays from the top and bottom of a tree cross through a pinhole and make an upside-down tree on a screen.
Question 7: sketch the inverted tree. Rays continue straight through the pinhole. Tap to view at full size.

8. Write your name on a piece of paper and hold it in front of a plane mirror such that the paper is parallel to the mirror. Sketch the image. What difference do you notice? Explain the reason for the difference.

ANSWER In the mirror image, the letters of the name appear reversed from left to right and read backwards. For example, the name “RITA” would appear written as its left–right mirrored form. The image is still erect (not upside down) and the same size as the writing. Reason: this left–right reversal is called lateral inversion. A plane mirror always laterally inverts the image, which is why the word that is on your left appears on the right in the mirror. This is the same reason the word ‘AMBULANCE’ is written reversed on the front of an ambulance — so that drivers ahead read it correctly in their rear-view mirror.
RITA written normally and its horizontally mirrored form, with T and O unchanged in a symmetric block font.
Question 8: replace RITA with your own name. The shapes of individual letters are mirrored as well as their order. Tap to view at full size.

9. Measure the length of your shadow at 9 AM, 12 PM, and 4 PM with the help of your friend. Write down your observations:(i) At which of the given times is your shadow the shortest?(ii) Why do you think this happens?

ANSWER(i) The expected classroom answer is around noon, usually 12 PM among these readings. Record your actual measurements on the same level surface rather than inventing lengths.(ii) A shadow is shortest when the Sun is highest in the sky, at local solar noon. This need not coincide exactly with 12:00 on the clock, and the Sun need not be directly overhead. A lower Sun gives a longer shadow. Never look directly at the Sun.

10. On the basis of following statements, choose the correct option.Statement A: Image formed by a plane mirror is laterally inverted.Statement B: Images of alphabets T and O appear identical to themselves in a plane mirror.(i) Both statements are true(ii) Both statements are false(iii) Statement A is true, but statement B is false(iv) Statement A is false, but statement B is true

ANSWER Correct option: (i) Both statements are true. Statement A is true — a plane mirror always produces a laterally inverted image. Statement B is also true: the letters T and O are symmetrical about a vertical axis, so their left and right halves are mirror copies of each other. Hence even after lateral inversion they look exactly the same as themselves in the mirror.

11. Suppose you are given a tube of the shape shown in the Fig. 11.20 and two plane mirrors smaller than the diameter of the tube. Can this tube be used to make a periscope? If yes, mark where you will fix the plane mirrors.

ANSWERYes. Fig. 11.20 has both openings facing the same side. Fit one mirror at each of its two right-hand bends. In the side view, tilt the upper mirror like \ and the lower like /, each at 45° to the straight sections, with reflecting faces towards the light path.Light enters the upper opening, reflects downwards, then reflects towards the eye at the lower opening. The mirror planes are perpendicular in this arrangement, not parallel. Parallel mirrors are used in the usual Z-shaped periscope with openings facing opposite ways.
U-shaped tube with both openings left: upper backslash mirror reflects light down, lower slash mirror reflects it left to the eye.
Question 11: mirror positions for the tube actually shown in NCERT Fig. 11.20. Arrows show the light path. Tap to view at full size.

12. We do not see the shadow on the ground of a bird flying high in the sky. However, the shadow is seen on the ground when the bird swoops near the ground. Think and explain why it is so.

ANSWERThe Sun is an extended light source. For a bird high above the ground, light from different parts of the Sun casts slightly displaced shadows. Much of the ground receives some sunlight, and the fully dark region may not reach it, so the shadow is blurred and too faint to notice.Near the ground, these shadows overlap more closely and give a sharper, darker outline. This is caused by the Sun’s apparent size and the object-screen distance, not by light simply bending around the bird.

Extra Practice Questions

These questions and MCQs are ClearStudy practice, separate from the NCERT exercise.

Short Answer Type Questions

Q1. Why is the Moon called a non-luminous object?

ANSWERThe Moon does not emit its own light. We see it only because it reflects the light of the Sun that falls on it, so it is non-luminous.

Q2. State two activities from the chapter that show light travels in a straight line.

ANSWER(i) The matchbox activity: a light spot is seen on the screen only when the holes of all three matchboxes are exactly in a line. (ii) The bent-pipe activity: a candle flame is visible through a straight pipe but not through a bent pipe.

Q3. What three things are needed to obtain a shadow?

ANSWERA source of light, an opaque object, and a screen (such as a wall, floor or ground) on which the shadow is formed.

Q4. List any three properties of the image formed by a plane mirror.

ANSWERIt is erect, the same size as the object, laterally inverted, and cannot be obtained on a screen (any three of these).

Q5. How does a shiny steel plate produce a bright spot on the opposite wall?

ANSWERThe shiny surface reflects the light falling on it and changes its direction. The reflected light travels in a straight line to the wall and forms a bright spot there. This change of direction by a shiny surface is called reflection of light.

Long Answer Type Questions

Q1. Classify materials as transparent, translucent and opaque with respect to how light passes through them, giving one example of each and stating the kind of shadow each forms.

ANSWERTransparent materials let light pass almost completely through them, e.g. clear glass; they form only a faint shadow, if any. Translucent materials let light pass partially, e.g. tracing paper or thin cloth; they form a lighter, blurred shadow. Opaque materials do not let light pass at all, e.g. cardboard or wood; they form a dark, well-defined shadow. The amount of light blocked decides how dark the shadow is, which is why opaque objects make the darkest shadows and transparent objects make the faintest.

Q2. Explain how a pinhole camera forms an image. Why is the image inverted?

ANSWERA pinhole camera is a box with a tiny hole on one face and a translucent screen on the opposite face. Light rays coming from each point of a bright object travel in straight lines and pass through the pinhole. Because light travels in a straight line, the rays from the top of the object pass through the hole and strike the lower part of the screen, while rays from the bottom reach the upper part. The crossing of these straight rays at the small hole flips the picture, so the image formed on the screen is upside down (inverted). The image also shows the colours of the object. Moving the screen nearer or farther changes the size of this image.

Q3. With the help of the reflection of light, explain how a periscope helps us see objects that are not directly visible.

ANSWERA periscope is made by fixing two plane mirrors inside a Z-shaped (or bent) tube, each tilted at about 45° and facing each other. Light from an object that we cannot see directly — because a wall or a crowd blocks the straight path — enters the top opening and falls on the upper mirror. The mirror reflects it and changes its direction so that it travels down the tube. At the bottom, the second mirror reflects the light again towards the eye. Since reflection only changes the direction of light without distorting it, the observer sees a clear image of the hidden object. This is why periscopes are used in submarines, tanks and by soldiers to look out from behind cover.

MCQs & Assertion–Reason

1. Which of the following is a luminous object?

(a) Moon    (b) Mirror    (c) Sun    (d) Venus

2. The matchbox-hole activity shows that light:

(a) bends around corners    (b) travels in a straight line    (c) needs water to travel    (d) cannot pass through holes

3. Light passes partially through a material that is:

(a) transparent    (b) opaque    (c) translucent    (d) luminous

4. To observe a shadow we need a source of light, a screen and:

(a) a transparent object    (b) an opaque object    (c) a mirror    (d) water

5. Changing the colour of an opaque object changes the colour of its shadow:

(a) always    (b) never    (c) only in sunlight    (d) only for red objects

6. The change in the direction of light when it falls on a mirror is called:

(a) refraction    (b) shadow    (c) reflection    (d) absorption

7. The image formed by a plane mirror is:

(a) inverted and smaller    (b) erect and the same size    (c) inverted and larger    (d) erect and smaller

8. The left–right reversal in a mirror image is called:

(a) refraction    (b) lateral inversion    (c) reflection    (d) dispersion

9. The image formed by a pinhole camera is:

(a) erect    (b) laterally inverted only    (c) upside down (inverted)    (d) not formed at all

10. A periscope and a kaleidoscope are made using:

(a) lenses    (b) plane mirrors    (c) prisms    (d) coloured glass only

Answer key: 1-(c), 2-(b), 3-(c), 4-(b), 5-(b), 6-(c), 7-(b), 8-(b), 9-(c), 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: The Moon is a non-luminous object.

Reason: The Moon does not emit its own light and is seen only by reflecting sunlight.

A-R 2. Assertion: A shadow is formed behind an opaque object.

Reason: Light travels in a straight line and is blocked by the opaque object.

A-R 3. Assertion: The word ‘AMBULANCE’ is written reversed on the front of an ambulance.

Reason: A plane mirror laterally inverts the image, so a driver ahead reads it correctly in the rear-view mirror.

A-R 4. Assertion: A candle flame can be seen through a bent pipe.

Reason: Light travels in a straight line.

A-R 5. Assertion: A shadow becomes smaller and sharper when the object is moved closer to the screen.

Reason: The image formed by a plane mirror is virtual and laterally inverted.

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

Quick Revision Summary

  • Luminous objects emit their own light (Sun, stars, fire, fireflies); non-luminous objects only reflect light (Moon, mirror).
  • Light travels in a straight line — shown by the matchbox-hole and bent-pipe activities.
  • Light passes fully through transparent, partly through translucent, and not at all through opaque materials.
  • A shadow needs a light source, an opaque object and a screen; the colour of the object does not change the colour of the shadow.
  • Reflection is the change in direction of light by a mirror or shiny surface.
  • A plane-mirror image is erect, same size, laterally inverted, and cannot be caught on a screen.
  • A pinhole camera forms an inverted image; periscopes (2 mirrors) and kaleidoscopes (3 mirrors) use reflection.

Common Mistakes to Avoid

  • Calling the Moon or a mirror “luminous” — they only reflect light, so they are non-luminous.
  • Mixing up lateral inversion (left–right reversal in a mirror) with the upside-down image of a pinhole camera.
  • Saying a shadow takes the colour of the object — a shadow is always dark, whatever the object’s colour.
  • Thinking the shadow is largest when the object is near the wall — it is largest when the object is near the light source.
  • Believing the plane-mirror image can be caught on a screen — it is a virtual image and cannot be obtained on a screen.
  • Copying one mirror arrangement into every tube — use the ray path: Z-shaped and same-side U-shaped tubes need different relative mirror tilts.

How to write a clear answer

Always link your answers to the rule that light travels in a straight line — it explains shadows, the bent pipe and the pinhole camera. When describing a plane-mirror image, give all four properties (erect, same size, laterally inverted, not on a screen). For numerical or activity-based questions on shadow size, remember: object near the light → bigger shadow; object near the screen → smaller, sharper shadow. Use the textbook devices — periscope and kaleidoscope — as examples of reflection to show you have read the chapter.

Frequently Asked Questions

What is Class 7 Science Curiosity Chapter 11 about?

Chapter 11, Light: Shadows and Reflections, explains that light travels in a straight line and uses this idea to teach luminous and non-luminous objects, transparent/translucent/opaque materials, how shadows form, reflection in a plane mirror, the inverted image of a pinhole camera, and devices like the periscope and kaleidoscope.

Why does a plane mirror show your writing reversed?

A plane mirror produces a laterally inverted image — left and right are swapped. So writing held in front of a mirror appears reversed left-to-right, which is also why ‘AMBULANCE’ is printed reversed on vehicles so drivers ahead read it correctly in the rear-view mirror.

Why is the image in a pinhole camera upside down?

Because light travels in straight lines, rays from the top of the object pass through the tiny hole and land on the lower part of the screen, while rays from the bottom land on the upper part. This crossing flips the picture, so the image is inverted.

Are these Class 7 Science Curiosity Chapter 11 solutions free?

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

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