NCERT Solutions for Class 7 Science Curiosity Chapter 11 Question Answer PDF

 NCERT Solutions for Class 7 Science Curiosity Chapter 11 provide clear and simple explanations for all the important concepts related to light, shadows, and reflections. These solutions help students understand how light travels, how shadows are formed, and how images are reflected in mirrors. 

With easy-to-follow answers and well-explained activities, these solutions are perfect for revision and exam preparation. If you're looking for accurate Class 7 Science Chapter 11 question answer, these NCERT solutions are a helpful resource to strengthen your understanding and improve your scores.

NCERT Solutions for Class 7 Science Curiosity Chapter 11 Introduction

 In Chapter 11 of Class 7 Science  Light, Shadows and Reflections, students learn about how light travels, how shadows are formed, and how mirrors help us see reflections. This chapter explains important ideas like the difference between transparent, translucent, and opaque objects, and how light travels in a straight line.

It also talks about how shadows change in size depending on the position of the object and the light source. Students will also explore mirror images, lateral inversion, and the working of a pinhole camera.

These concepts are explained through simple activities and real-life examples, helping students become curious about how light behaves in everyday life. 

NCERT Solutions for Class 7 Science Curiosity Chapter 11 provide easy-to-understand answers to all textbook questions and follow the latest  CBSE syllabus. They are helpful for revision, exams, and building a strong base in science.

Class 7 Science Chapter 11 Question Answer

Here are the solutions for Class 7 Chapter 11 Science Light, Shadows and Reflections: 

Activity 11.1: Let us investigate Take three matchboxes and make a hole in the inner tray of each matchbox, exactly at the same position.  Arrange these three matchboxes in a straight line. Make sure that all three holes are exactly at the same height and are in a line as shown in Fig. 11.4. 

Place a torch light on one side of the matchboxes, ensuring that its lamp is at the height of the holes.  

Place a cardboard (screen) on the other side of the matchboxes and obtain a bright spot on it. (You may need to slightly adjust the heights of boxes.)  

Move one of the matchboxes slightly to a side or up and down.

Are you able to obtain the light spot on the screen now? 

Answer: When all three matchboxes are in a straight line with holes at the same height, the torch light passes through them, and we see a bright spot on the screen. But when we move one matchbox a little to the side or up/down, the light gets blocked, and the spot disappears.

Conclusion:  Light travels in a straight line. If the path is blocked, light can’t pass through.

Answer : When the pipe is straight, you can see the candle flame clearly through it. But when the pipe is bent, you can’t see the flame anymore.

Conclusion:
Light travels in a straight line. If the path is bent, light cannot pass through, and we can’t see the flame.

Activity 11.3: Let us experiment 

 Collect objects made of diff erent materials. Also, you will need a torch.

List the materials of the objects in Table 11.1 and classify them into transparent, translucent, and opaque (In the chapter ‘Materials Around Us’ in the Grade 6 Science textbook Curiosity you learnt to classify materials into transparent, translucent, and opaque, depending on how you could see through them).

  Go to a dark room, turn on the torch, and place it at such a position that you get a spot of light from the torch on a wall. Or you may place a cardboard screen as shown in Fig. 11.6 and get the spot of light on it.  We will now conduct this activity in two parts — prediction and observation.  

Predict what will happen if you hold an object in front of the light coming out of the torch. Would you continue to see the spot of light on the screen? 

Note your prediction in Table 11.1.  Now, actually place the object between the torch and the screen. Does light pass through the object? Note your observation in Table 11.1.  Repeat this for all the objects.

Answer: In this activity, we use a torch and different materials to check how much light passes through each. We first predict, then observe.

What happens when an object comes in the path of light?

When we place an object in the path of light, it either allows the light to pass fully, partially, or not at all, depending on the material.

Laser Beam Activity (Teacher Supervision Needed)

When we pass a laser beam through a beaker with water and a drop of milk:

• We see the laser beam clearly inside the water.

• The beam follows a straight line.

This shows that light travels in a straight path.

Conclusion:

• Transparent materials allow all light to pass through (like glass, water).

• Translucent materials allow some light (like tracing or wax paper).

• Opaque materials block all light (like cardboard, thick cloth).

• Light travels in a straight line, which we can observe using a torch or a laser.

Activity 11.4: Let us explore  

Collect some opaque objects of different shapes and sizes.  

Repeat Activity 11.3, but this time, carry out the actions mentioned in the first column of Table 11.2.  

Observe the shape and size of the shadow on the screen for each of the actions. Did the shadow form in all cases? Was the shape and size of the shadow the same as the object?  Record your observations in the second column of Table 11.2.

 What conclusions do you draw from this activity? What do we need to observe a shadow? Does the colour of the shadow change when the colour of the object is changed?

 Answer: We use a torch, a screen, and different opaque objects to observe how shadows are formed. We also check what happens when we change the setup.

Conclusion:

• A shadow is formed only when we have a light source, an opaque object, and a screen.
  
  

• The size and shape of the shadow depend on the position and angle of the object.
  
  

• Changing the color of the object does not change the color of the shadow.
  
  

• Light travels in a straight line, and the shadow forms where light is blocked.

Activity 11.5: Let us investigate 

 Find a shiny flat steel plate or a plane mirror, that is, a mirror that is flat and not curved.  Take it outside and let the sunlight fall on the shiny surface. What can you do to redirect light on the wall on which the sunlight is not falling directly?

Turn the shiny plate or mirror in different directions to redirect the light onto a wall or a nearby surface (Fig. 11.8). Do you see a spot of light on the wall? Does it mean that the shiny plate or mirror has changed the direction of light? 

 Now, tilt the shiny plate or mirror in different ways and observe the light spot on the wall. Does it change position? Notice how light always travels in straight lines and changes direction when it falls on the shiny plate or mirror.

Answer: When you take a shiny steel plate or a plane mirror outside and let sunlight fall on it, you can tilt the mirror to make the sunlight fall on a wall or another surface where sunlight was not reaching directly.

Observation: By changing the angle of the mirror or shiny plate, you can redirect the sunlight to another place.

Conclusion: A shiny surface or a mirror can change the direction of light that hits it. This is called the reflection of light.

Activity 11.6: Let us experiment Fig. 11.8: 

Using mirror to redirect sunlight on a wall  Turn the shiny plate or mirror in diff erent directions to redirect the light onto a wall or a nearby surface (Fig. 11.8). Do you see a spot of light on the wall? 

Does it mean that the shiny plate or mirror has changed the direction of light?  

Now, tilt the shiny plate or mirror in diff erent ways and observe the light spot on the wall. Does it change position? 

Notice how light always travels in straight lines and changes direction when it falls on the shiny plate or mirror.  

Take a plane mirror with stand, a torch, a comb, a sheet of white paper, and a strip of black paper.  Using the black paper, close all openings of the comb, except for one to make a thin slit.  

Spread a white paper on a table, hold the comb perpendicular to the sheet of paper and shine the torch light on the slit. Adjust the comb and torch slightly till you see a thin beam of light along the paper which has passed through the slit (Fig. 11.9a).  

Now, place the mirror in the path of the light beam while keeping the comb steady (Fig. 11.9b). What do you observe?

Answer:Part 1  Using Mirror or Shiny Plate

• When you turn a shiny plate or mirror, a bright spot of light appears on a nearby wall or surface.

• When you tilt the mirror, the light spot moves to a different place.

Conclusion:  Yes, the shiny plate or mirror changes the direction of light, which is called reflection. Light always travels in a straight line, but it bounces off when it hits a mirror.

Part 2  Light Beam and Mirror Experiment

Materials: Torch, comb, white paper, black paper, and a plane mirror.

1. Cover the comb with black paper, leaving only one slit open.

2. Shine a torch through the slit so a thin beam of light falls on the white paper.

3. Place a mirror in the path of this beam.

Observation: The beam of light changes direction after hitting the mirror.

Conclusion:

• Light travels in a straight line.

• When it hits a mirror, it reflects (bounces off) in a new direction.

• This change in direction is called the reflection of light.

Activity 11.7: Let us experiment

 Take a plane mirror and a pen or some other object.  Place the pen in front of the mirror as shown in Fig. 11.10. What do you see in the mirror? 

It appears as if a similar pen is placed behind the mirror. The pen which appears behind the mirror is the image of the pen formed by the mirror. 

The pen itself is the object.

  Now, move the pen to different positions in front of the mirror and compare the sizes of the images of the pen at each position. Are the two sizes the same?

 The image formed by a plane mirror is of the same size as the object.  Again, move the pen to different positions in front of the mirror and observe if the image is upright at each position. 

Does the tip of the pen appear on top at each position? An upright image is called erect. An image formed by a plane mirror is erect. 

 Now, place a screen vertically behind the mirror. Move it around. Do you get the image on the screen? Repeat this by placing the screen in front of the mirror. The image formed by a plane mirror cannot be obtained on a screen.

Answer

Steps and Observations:

1. Place a pen in front of a plane mirror.

• You will see a similar pen behind the mirror. This is the image of the real pen (object).

2. Move the pen to different positions in front of the mirror.

• The image size remains the same as the pen, no matter how far or close you keep it.

• The image is always upright (erect) – the tip stays at the top.

3. Place a screen behind the mirror.

• No image appears on the screen.

• Even if you put the screen in front of the mirror, the image doesn’t fall on it.

Conclusion:

• A plane mirror forms an image that is:

• Same in size as the object,

• Erect (upright),

• But the image cannot be caught on a screen (it is a virtual image).

Activity 11.8: Let us experiment 

 Stand in front of a plane mirror and look at your image (Fig. 11.11). Notice how far it appears to be from the mirror.  Now, stand close to the mirror. Is the image also closer to the mirror?  Stand at different distances from the mirror and notice how far the image appears to be from the mirror in each case. 

Do you find any relation between your distance from the mirror and the distance of your image from the mirror?

You might have noticed that when you stand close to the plane mirror, the image also appears to be close to the mirror. The image appears to be far from the mirror when you stand far from the plane mirror.  Raise your left arm. Which arm does your image raise?  Touch your right ear. Which ear does your image touch?

Answer:

 Steps and Observations:

1. Stand in front of a plane mirror and look at your image.

• The image appears to be the same distance behind the mirror as you are in front of it.

2. Move closer to the mirror.

• The image also appears closer to the mirror.

3. Move farther away from the mirror.

• The image also appears farther behind the mirror.

So, the distance of the image from the mirror is equal to your distance from the mirror.

More Observations (Lateral Inversion):

• If you raise your left arm, your image raises the right arm.

• If you touch your right ear, your image appears to touch the left ear.

Conclusion:

• A plane mirror forms an image that:

• Is at the same distance behind the mirror as the object is in front.

• Is laterally inverted (left appears right and right appears left).

• Is same in size and erect (upright).

Activity 11.9: Let us explore Caution 

 Use a lighted candle under adult supervision only.  Take a piece of cardboard and a candle. Make a small hole in the cardboard.  In a dimly lit room, position the cardboard at a short distance from a screen.  

Place a lighted candle in front of it as shown in Fig. 11.12a. What do you see on the screen? 

Light coming from the flame passes through the hole on the cardboard and forms an image of the candle flame on the screen. Do you notice anything surprising? The image of the candle flame is upside down, that is, inverted. Let us now make a pinhole camera, which you can use outdoors.

Answer:

 Steps and Observations:

1. Take cardboard and make a small hole in it.

2. In a dim room, place the cardboard a little distance in front of a screen (like white paper).

3. Put a lighted candle in front of the hole (as shown in Fig. 11.12a).

What do you see?
A n image of the candle flame appears on the screen.
Surprisingly, the image is upside down (inverted).

Conclusion:

• Light passes in a straight line through the hole.

• It forms an inverted image of the candle flame on the screen.

• This shows how a pinhole camera works  it captures real but inverted images using light that travels in a straight path.

Activity 11.10: Let us construct 

Take two boxes of cardboard such that one can slide into another with very little gap in between them. Cut open one side of each box.  

On the opposite face of the larger box, make a small hole in the middle (Fig. 11.13a). 

 On the opposite face of the smaller box, cut out a square from the middle with a side of about 5–6 cm. Cover this opening with a thin translucent paper (like a tracing paper) to form a screen (Fig. 11.13b).  

Slide the smaller box inside the larger one in such a way that the side with the tracing paper is inside (Fig. 11.13c). 

Answer:

Steps:

1. Take two cardboard boxes, where one can easily slide into the other.

2. Cut open one side of each box.

3. On the opposite side of the larger box, make a small hole in the center. This will act as the pinhole.

4. On the opposite side of the smaller box, cut a square opening (5–6 cm) in the middle.

5. Cover the square opening with thin translucent paper like tracing paper. This will be your screen.

6. Slide the smaller box into the larger one so that the tracing paper side goes inside.

Conclusion:

You have now made a simple pinhole camera!

• When you point the pinhole side toward a bright object (like a candle or tree in sunlight), you will see its inverted image on the tracing paper screen.

• This works because light travels in straight lines and forms an image inside the box.

Light, Shadows and Reflections – InText Questions 

Question 1: What happens when an opaque object blocks the path of light? (Page 157)

 Answer:
When an opaque object blocks light, it doesn’t let the light pass through. This creates a dark patch behind it, called a shadow.

Question 2: When the opaque object was a shiny object like a polished steel plate, I got a shadow on the screen, but I also saw that there was a bright spot of light on the wall on the opposite side. Why was it so? (Page 15) 

Answer:
A shiny object like a steel plate blocks light (makes a shadow), but it also reflects some light, which forms a bright spot on the wall.

Question 3: In a mirror, I can also see my face. Is that also due to the reflection of light? (Page 160)

Answer:
Yes, we see our face in the mirror because light reflects from the mirror back to our eyes.

Question 4:Oh! Now I realise why is written on an ambulance. It reads ‘AMBULANCE’ when viewed from the rear-view mirrors of the vehicle ahead of the ambulance. (Page 162) 

Answer:
It is written in mirror writing so that drivers in front see it correctly in their rear-view mirrors, due to lateral inversion caused by reflection.

Question 5: Can we see an image of an object only in a mirror or are there some other ways as well? (Page 162)

 Answer:
No, not just mirrors. We can also see images on screens, through clear materials, or by using a pinhole camera.

Let Us Enhance Our Learning

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

Answer:

The Sun and the Pole Star are luminous objects because they give out their own light. Mars, Moon, Venus, and Mirror are not luminous because they do not produce light on their own they just reflect light from other sources like the Sun.

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

Answer:

Question 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:
Rekha can see the candle flame because light travels in a straight line, and only her line of sight is straight through the pipe. The others are not in line with the flame, so they cannot see it.

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

Answer:
The correct image is option (d).

When light falls on the boy from one side, the shadow is formed on the opposite side. So, the shadow will appear away from the light source, just like in image (d).

Question 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).

Answer:
In scenario (i), the ball is close to the torch, so the shadow is big and blurry. The correct option is (b).

In scenario (ii), the ball is close to the wall, so the shadow is small and clear. The correct option is (a).

Question 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:

Question 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.
Answer:
The image of the tree formed in the pinhole camera is shown.

Question 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:
When you look at your name in the mirror, it looks flipped from left to right. This is because a mirror shows a laterally inverted image, so the letters appear backward.

Question 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) Your shadow is shortest at 12 PM.

(ii) At 12 PM, the Sun is right above you, so your body blocks less light, making the shadow short.

(i) Both statements are true. Plane mirrors create a laterally inverted image (left to right is reversed), and some alphabets like T and O appear the same in a plane mirror.

Question 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.

Answer:
Yes, we can make a periscope. Place the two mirrors at 45° angles, facing each other, inside the tube. This way, the light reflects between them, and you can see around corners.

Question 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.
Answer:
When a bird flies high, the shadow becomes tiny and faint, so we don’t notice it. But when the bird is close to the ground, it blocks more light and makes a clearer, bigger shadow.

Class 7 science Curiosity Chapter 11 Question Answer PDF Download

Students can download the Ncert Solutions for Class 7 Science curiosity Chapter 11 question answer PDF using the link below. The PDF includes all solved in-text and exercise questions from the NCERT Curiosity textbook. These well-organized solutions are perfect for quick revision and self-study.

Benefits of Using NCERT Solutions for Class 7 Science Curiosity Chapter 11

Here are the benefits of using NCERT Solutions for Class 7 Science Curiosity Chapter 11  Light, Shadows and Reflections:

1.  The solutions explain each topic like shadows, reflection, and image formation in simple language, helping students understand easily.

2. These solutions include both in-text and exercise questions which are often asked in exams.

3. Students can quickly complete their homework using these step-by-step answers.

4. It strengthens basic science concepts, which is helpful for higher classes.

5. Well-organized answers help students revise the whole chapter quickly before exams.