NCERT Solutions for Class 7 Science Curiosity Chapter 11: Light, Shadows and Reflections by PW

Light is present in observations, but questions about its behaviour can be confusing. Seeing a shadow, viewing an image in a mirror or noticing a candle through a straight pipe requires you to understand how light travels and interacts with materials.

Concepts such as luminous objects, transparent and opaque materials, shadow size and image formation can become difficult when their applications are tested through questions.

The NCERT Solutions Class 7 Science Curiosity Chapter 11 provide answers to questions from Light: Shadows and Reflections. They explain straight-line propagation, shadow formation, pinhole cameras, plane mirrors, lateral inversion and periscopes, helping you revise concepts clearly.

Class 7 Science Curiosity Chapter 11 NCERT Solutions

The following solutions cover questions based on the properties of light, formation of shadows and images, reflection and related optical devices.

1. Which of the following objects are luminous (emit their own light)?

A) Mars and Moon
B) Mirror and Venus
C) Pole Star and Sun
D) Moon and Mirror

Answer: C) Pole Star and Sun

Luminous objects produce their own light. The Sun and Pole Star are examples of luminous objects, while the Moon, Mars and Venus are visible because they reflect light.

2. What type of image is formed by a pinhole camera?

A) Virtual and upright
B) Real and inverted
C) Laterally inverted and magnified
D) Diminished and upright

Answer: B) Real and inverted

A pinhole camera forms a real and inverted image because light travels in straight lines through the small opening and forms an image on the opposite screen.

3. An object that blocks light completely and forms a distinct shadow is called a/an:

A) Transparent object
B) Translucent object
C) Opaque object
D) Luminous object

Answer: C) Opaque object

Opaque objects do not allow light to pass through them. When light falls on such an object, it can produce a distinct shadow behind it.

4. Through which type of material does light pass almost completely?

A) Opaque object
B) Transparent object
C) Translucent object
D) Luminous object

Answer: B) Transparent object

Transparent materials allow most of the light falling on them to pass through. Clear glass is a common example of a transparent material.

5. Why can a person see a candle flame only through a straight pipe and not a bent pipe?

A) Light travels in a straight line.
B) Light bends around obstacles easily.
C) Light is absorbed by straight pipes.
D) The flame emits light only in one direction.

Answer: A) Light travels in a straight line.

The candle flame can be seen through a straight pipe because light travels along a straight path. A bent pipe changes the path, preventing the light from reaching the observer directly.

6. At what time of the day is a shadow formed by sunlight the shortest?

A) 9 AM
B) 12 PM (Noon)
C) 4 PM
D) 6 PM

Answer: B) 12 PM (Noon)

At around noon, the Sun is highest in the sky and sunlight falls more directly on objects. As a result, the shadow formed is shortest.

7. Why is a person's shadow shortest at 12 PM (Noon)?

A) The Sun is low in the East.
B) The Sun is almost overhead and its rays fall vertically.
C) The Sun stops emitting light at noon.
D) The Sun is low in the West.

Answer: B) The Sun is almost overhead and its rays fall vertically.

When the Sun is nearly overhead, its rays fall more vertically on the person. This produces a shorter shadow compared with the shadows formed when the Sun is lower in the sky.

8. What happens to the size of a shadow on a screen when an opaque object is moved closer to the light source (torch)?

A) The shadow becomes smaller and sharper.
B) The shadow becomes larger and blurry.
C) The shadow disappears completely.
D) The shadow size remains unchanged.

Answer: B) The shadow becomes larger and blurry.

Moving the opaque object closer to the torch allows the light rays to spread around it before reaching the screen. This makes the shadow appear larger and less sharp.

9. What happens to the shadow on a screen when an opaque object is moved closer to the wall (screen) and farther from the light source?

A) The shadow becomes smaller and sharp.
B) The shadow becomes larger and blurry.
C) Two shadows are formed.
D) No shadow is formed.

Answer: A) The shadow becomes smaller and sharp.

When the opaque object is closer to the screen and farther from the light source, the shadow generally becomes smaller and more distinct.

10. What phenomenon causes the left side of an object to appear as the right side in a plane mirror?

A) Rectilinear propagation
B) Lateral inversion
C) Dispersion of light
D) Shadow formation

Answer: B) Lateral inversion

Lateral inversion is the apparent reversal of the left and right sides of an object in its plane-mirror image.

11. Which of the following capital English letters appear completely identical to themselves in a plane mirror due to symmetry?

A) F and P
B) T and O
C) R and J
D) B and E

Answer: B) T and O

The capital letters T and O have vertical symmetry, so their mirror images appear identical to the original letters.

12. What instrument can be made using two plane mirrors placed in a Z-shaped or U-shaped tube to see objects out of direct line of sight?

A) Microscope
B) Pinhole camera
C) Periscope
D) Telescope

Answer: C) Periscope

A periscope uses plane mirrors to change the direction of light. It allows a person to view objects that are not directly in their line of sight.

13. Why is the shadow of a bird flying high in the sky not clearly visible on the ground?

A) Birds do not block light.
B) High in the sky, the shadow falls far away, becomes very faint, and spreads out over a large area.
C) Sunlight cannot reach birds high up.
D) Birds absorb all light falling on them.

Answer: B) High in the sky, the shadow falls far away, becomes very faint, and spreads out over a large area.

When the bird is very high above the ground, its shadow becomes spread out and faint. Therefore, it may not be clearly visible from the ground.

14. When does the shadow of a bird become clearly visible on the ground?

A) When it flies higher into the clouds.
B) When it stops flying and stays still in high air.
C) When it swoops near the ground.
D) Only during night time.

Answer: C) When it swoops near the ground.

When the bird comes closer to the ground, its shadow becomes smaller and more distinct, making it easier to see.

15. If two torches are placed on one side of a ball in front of a screen, how many shadows will appear on the screen?

A) One shadow
B) Two shadows
C) No shadow
D) Four shadows

Answer: B) Two shadows

Each torch acts as a separate light source. The ball blocks light from both torches, resulting in two shadows appearing on the screen.

NCERT Solutions for Class 7 Science Curiosity Chapter 11 PDF

For quick reference during practice, having the chapter questions and their answers in one place can be useful. The Class 7 Science Curiosity Chapter 11 Solutions PDF covers questions on luminous objects, shadows, reflection, image formation, pinhole cameras and periscopes.

Why Choose NCERT Class 7 Science Chapter 11 Solutions by PW?

The NCERT Class 7 Science Chapter 11 Solutions by PW help you understand important concepts related to light through simple explanations and everyday examples. They can make it easier to revise the chapter, understand activity-based questions and connect scientific concepts with observations around you.

• Identify Luminous Objects: Learn to distinguish between objects that produce their own light and those that are visible because they reflect light.

• Understand Light Propagation: Understand why light travels in a straight line and how this principle affects the way objects become visible.

• Classify Materials: Learn the differences between transparent, translucent and opaque materials based on how they allow light to pass through them.

• Explore Shadow Formation: Understand how the positions of the light source, object and screen affect the formation and size of a shadow.

• Learn About Pinhole Cameras: Understand how a small opening can form a real and inverted image of an object.

• Understand Plane Mirror Images: Learn how images are formed in plane mirrors and understand the concept of lateral inversion.

• Explore Periscopes: Understand how plane mirrors can be used in periscopes to view objects that are not directly visible.

• Observe Changes in Shadows: Learn why the size, shape and clarity of a shadow can change when the position of the object or light source changes.

Understanding shadows and reflections can help children learn how light behaves in different situations. The NCERT Class 7 Science Chapter 11 Solutions explain questions related to light sources, materials, shadow formation, image formation and optical devices. Practising these questions can help children connect everyday observations with the concepts of light and develop a better understanding of the chapter.

Related Resources

• CBSE Class 7 Science Syllabus

• CBSE Class 7 Science NCERT Solutions

• CBSE Class 7 Science Sample Papers

• CBSE Class 7 Science Notes