Question 1
Which are luminous objects: Mars, Moon, Pole Star, Sun, Venus, or a mirror?
Steps only
Luminous objects produce their own light.
Answer
Pole Star and Sun.
CLASS 7 · SCIENCE · CHAPTER 11
Light: Shadows and Reflections
Simple answers to all 12 end questions, with sample explanations for the chapter’s light and mirror projects.
16 worked answersComplete chapter answers
16 worked answers · short steps first, explanations when you need them
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Textbook pages chapter end
Question 2
Match: pinhole camera, opaque object, transparent object, and shadow with their descriptions: blocks light completely; dark region formed behind an object; forms an inverted image; lets almost all light pass through.
Steps only
Match each term to the way it affects light.
Answer
Pinhole camera: inverted image; opaque: blocks; transparent: passes light; shadow: dark region.
Question 3
In the figure with four students and pipes, who can see the candle flame? Explain.
Steps only
Choose the student whose pipe makes a straight path from flame to eye.
Answer
The student looking through the straight pipe.
Question 4
Select the picture that correctly shows the boy’s shadow in the given light setup.
Steps only
The shadow forms opposite the Sun and joins the boy’s feet.
Answer
Image (d).
Question 5
Choose the correct shadow drawings for the two torch, ball, and screen arrangements shown in the figure.
Steps only
Near torch: larger shadow. Near wall: smaller shadow.
Answer
- (i) (b);
- (ii) (a).
Question 6
Match the torch and object arrangements with their shadow characteristics: torch close to ball; torch far from ball; ball removed; two torches used.
Steps only
Close torch: large; far torch: small; no ball: no shadow; two torches: two shadows.
Answer
Match by how each arrangement blocks light.
Question 7
Sketch the outline of the tree’s image formed in a pinhole camera.
Steps only
Draw an inverted tree outline on the screen.
Answer
The pinhole image is upside down.
Question 8
Write your name on paper, hold it parallel to a plane mirror, and sketch the image. What difference do you notice and why?
Steps only
A plane mirror reverses left and right.
Answer
The name appears laterally inverted.
Question 9
Measure your shadow at 9 AM, 12 noon, and 4 PM. (i) When is it shortest? (ii) Why?
Steps only
A higher Sun makes a shorter shadow.
Answer
Usually shortest around noon.
Question 10
Check the two statements: A plane-mirror images are laterally inverted. Images of the capital letters T and O look the same as the letters. Which statements are true?
Steps only
The mirror reverses left and right, but T and O are symmetric.
Answer
Both statements are true.
Question 11
Can the angled tube in the figure be used as a periscope? If so, where should the mirrors be placed?
Steps only
Put two parallel mirrors at the bends, each at about 45° to the tube.
Answer
Yes, the tube can work as a periscope.
Question 12
Why may we not see a bird’s shadow on the ground when it is high in the sky, but see it when it swoops near the ground?
Steps only
Far away the shadow spreads and fades; near the ground it looks darker and clearer.
Answer
The nearby bird casts a more noticeable shadow.
Exploratory Projects
Textbook pages chapter end
Question Project 1
Find out whether fireflies are seen locally, ask elders about earlier sightings, and create a story about possible reasons for change.
Steps only
Ask elders and research habitat, lighting, and pesticide changes before writing the story.
Answer
Protect dark, healthy habitats that fireflies need.
Question Project 2
Cover the torch with coloured transparent paper and shine it on an opaque object. Repeat with different colours. What colour is the shadow, and what does the observation show?
Steps only
The shadow is dark; the surrounding lit area looks coloured.
Answer
The object blocks the coloured light.
Question Project 3
Place two mirrors at an angle or parallel to each other. How does the arrangement affect the number of images?
Steps only
Measure the angle and count images; smaller angles generally show more images.
Answer
The number of images depends on the angle between the mirrors.
Question Project 4
Can a small piece of plane mirror form an image of a much larger object, such as a tree? Predict, then test it.
Steps only
A small mirror can form an image of a much larger object.
Answer
Yes. Image size does not have to match mirror size.