Class 7 Science · Original EZT practice
Light: Shadows and Reflections (Class 7 Science Chapter 11): straight lines, dark patches and mirror tricks
You cannot see around a corner, your shadow follows you every sunny afternoon, and a mirror shows a you that is quietly flipped left-to-right. All three come from one rule - light travels in straight lines. Below: the ideas in plain words, then original EZT practice with worked answers. (Note: this is original practice, not a textbook exercise key.)
10 original worked examples, 10 fresh self-check questions, with explained answers. These are not copied textbook exercises, an official chapter index or a full answer key. No affiliation with NCERT is claimed.
Official sources for topic and edition context, checked 17 October 2026:
1. Light travels in straight lines
In a uniform medium, light goes straight. That single fact explains sharp shadows, pinhole images, and why you cannot peek around a wall.
2. Transparent, translucent, opaque
Transparent objects let light through cleanly (clear glass); translucent ones let some through but scatter it (tracing paper, frosted glass); opaque ones block it entirely (wood, a book, you).
3. Shadows: blocked light
A shadow forms where an opaque object blocks light. Its size and shape change with the position of the light source - low sun, long shadow; sun overhead, short shadow. Only opaque objects cast sharp shadows.
4. Pinhole images: straight lines crossing
In a pinhole camera, light from the top of a candle travels straight through the tiny hole and lands at the bottom of the screen - and light from the bottom lands at the top. The image appears upside down (inverted) and smaller.
5. Reflection and plane mirrors
A plane mirror gives an image that is the same size as you, the same distance behind the mirror as you are in front, upright - and laterally inverted: left and right swap.
Choose, solve, check, then try a fresh question.
Before calculating, read the method prompt and name the condition that makes it useful. Write your own attempt. Open the steps only when you need them, and use the check to catch a wrong sign, unit or interpretation. Finish with the fresh question before reading its answer.
Why can you not see a friend standing behind a wall corner, though you can...
Choose the method: In a uniform medium, light goes straight.
EZT practice question
Why can you not see a friend standing behind a wall corner, though you can hear her?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: light travels in straight lines and cannot bend around the corner to your eyes; sound waves can bend around obstacles.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Sort these: clear glass, tracing paper, a steel spoon.
Choose the method: Transparent objects let light through cleanly (clear glass); translucent ones let some through but scatter it (tracing paper, frosted glass); opaque ones block it entirely (wood, a book, you).
EZT practice question
Sort these: clear glass, tracing paper, a steel spoon.
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: transparent - clear glass; translucent - tracing paper; opaque - steel spoon.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Why do bathroom windows often use frosted glass?
Choose the method: Transparent objects let light through cleanly (clear glass); translucent ones let some through but scatter it (tracing paper, frosted glass); opaque ones block it entirely (wood, a book, you).
EZT practice question
Why do bathroom windows often use frosted glass?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: it is translucent - it lets light in but scatters it, so shapes outside cannot be seen clearly.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Your shadow is very long in the morning and short at noon. Why?
Choose the method: A shadow forms where an opaque object blocks light.
EZT practice question
Your shadow is very long in the morning and short at noon. Why?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: the light source (the Sun) is low in the morning, so your body blocks light over a long stretch of ground; at noon the Sun is nearly overhead and the blocked patch shrinks beneath you.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Does a sheet of clear glass cast a shadow in sunlight?
Choose the method: A shadow forms where an opaque object blocks light.
EZT practice question
Does a sheet of clear glass cast a shadow in sunlight?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: barely - it is transparent, so light passes through and no clear dark patch forms.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Why is a pinhole camera's image inverted?
Choose the method: In a pinhole camera, light from the top of a candle travels straight through the tiny hole and lands at the bottom of the screen - and light from the bottom lands at the top.
EZT practice question
Why is a pinhole camera's image inverted?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: rays travel in straight lines through the hole, so the top of the object maps to the bottom of the screen and the bottom to the top.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Raise your right hand at a mirror. What does the image do?
Choose the method: A plane mirror gives an image that is the same size as you, the same distance behind the mirror as you are in front, upright - and laterally inverted: left and right swap.
EZT practice question
Raise your right hand at a mirror. What does the image do?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: it raises the hand on your left side - lateral inversion swaps left and right.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Why is AMBULANCE written in reverse on the front of the vehicle?
Choose the method: A plane mirror gives an image that is the same size as you, the same distance behind the mirror as you are in front, upright - and laterally inverted: left and right swap.
EZT practice question
Why is AMBULANCE written in reverse on the front of the vehicle?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: drivers ahead see it in their rear-view mirror, where the mirror's lateral inversion flips the reversed writing back to readable.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
How does a simple periscope let you see over a wall?
Choose the method: A plane mirror gives an image that is the same size as you, the same distance behind the mirror as you are in front, upright - and laterally inverted: left and right swap.
EZT practice question
How does a simple periscope let you see over a wall?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: two mirrors fixed at 45 degrees - the top one reflects the scene down the tube and the bottom one reflects it into your eye.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
The Moon shines brightly at night. Is it a source of light?
Choose the method: A plane mirror gives an image that is the same size as you, the same distance behind the mirror as you are in front, upright - and laterally inverted: left and right swap.
EZT practice question
The Moon shines brightly at night. Is it a source of light?
Show the worked solution
- Identify the source, object, material or mirror arrangement in the question.
- Trace the straight-line path, blocking or reflection of light.
- State the classification, shadow, image or reason in plain words.
Answer: no - the Moon has no light of its own; we see it by the sunlight it reflects.
Check: The answer follows straight-line travel, blocking or plane-mirror reflection without adding a bend that was not given.
Watch for this: Do not treat the Moon as a light source or translucent objects as fully transparent; reflection and scattering are different ideas.
Now try it yourself
Create one new example by changing the numbers, materials, object or setup and solve it by the same rule.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Try it yourself
Work these on paper before checking any notes. Answers are deliberately not shown here.
- Classify: butter paper, a wooden door, a clean window.
- What happens to your shadow's length as the Sun climbs?
- Why is a pinhole image upside down?
- Name two uses of plane mirrors in daily life.
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Questions about this practice page
- How does a shadow form?
- when an opaque object blocks light travelling in straight lines, the unlit patch behind it is the shadow.
- What is the difference between transparent, translucent and opaque?
- transparent passes light cleanly, translucent passes some but scatters it, opaque blocks it fully.
- Why is a mirror image laterally inverted?
- the mirror swaps left and right relative to the viewer - that is why your image raises the opposite hand and reversed writing reads correctly.
- Why is a pinhole camera image inverted?
- light travels straight through the hole, so rays from the top of the object land at the bottom of the screen.
- Are these the NCERT exercise questions for Light: Shadows and Reflections?
- No. EZT pages are original practice on this chapter - use them to prepare for the textbook exercises, not as a substitute for your book.