Скачать или смотреть Class8Science | Chapter 10 | Light: Mirrors & Lenses | Detailed Explanation | NCERT questions & Ans

#Class8Science| Chapter 10 | #Light: Mirrors and Lenses | Detailed Explanation | #NCERT questions & Ans
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All questions solution and explanation covered
1. A light ray is incident on a mirror and gets reflected by it
The angle made by the incident ray with the
normal to the mirror is 40°. What is the angle made by the
reflected ray with the mirror?

(i) 40° (ii) 50° (iii) 45° (iv) 60°

2. Fig. 10.22 shows three different situations where a light ray
falls on a mirror:
(i) The light ray falls along the normal.
Fig. 10.21
i r
Mirror
Fig. 10.23
(i) (ii) (iii)
20°
Mirror
Normal
Incident ray
Mirror
Incident ray
(a) (c)
Fig. 10.22
(b)
Mirror Incident ray
Match each image with the correct mirror.
Image Mirror
(i) Plane mirror
(ii) Convex mirror
(iii) Concave mirror
(ii) The mirror is tilted, but the
light ray still falls along the
normal to the tilted surface.
(iii) The mirror is tilted, and the
light ray falls at an angle of
20° from the normal.
Draw the reflected ray in each
case (Use a ruler and protractor
for accurate drawing). What is the
angle of reflection in each case?
3. In Fig. 10.23, the cap of a sketch pen is placed in front of three
types of mirrors.
Chapter 10.indd 166 6/28/2025 6:03:05 PM Chapter 10 — Light: Mirrors and Lenses 167
4. In Fig. 10.24 the cap of a sketch
pen is placed behind a convex
lens, a concave lens, and a flat
transparent glass piece — all at the
same distance.
Match each image with the correct
type of lens or glass.
Image Lens/glass type
(i) Flat transparent glass piece
(ii) Convex lens
(iii) Concave lens
5. When the light is incident along the normal on the mirror,
which of the following statements is true:
(i) Angle of incidence is 90°
(ii) Angle of incidence is 0°
(iii) Angle of reflection is 90°
(iv) No reflection of light takes
place in this case
6. Three mirrors—plane, concave
and convex are placed in
Fig. 10.25. On the basis of the
images of the graph sheet formed
in the mirrors, identify the
mirrors and write their names
above the mirrors.
7. In a museum, a woman walks towards a large
convex mirror (Fig. 10.26). She will see that:
(i) her erect image keeps decreasing in size.
(ii) her inverted image keeps decreasing in size.
(iii) her inverted image keeps increasing in
size and eventually it becomes erect and
magnified.
(iv) her erect image keeps increasing in size.
8. Hold a magnifying glass over text and identify
the distance where you can see the text bigger
than they are written. Now move it away
from the text. What do you notice? Which type of lens is a
magnifying glass?
(i) (ii) (iii)
Fig. 10.24
Fig. 10.25
Fig. 10.26
Chapter 10.indd 167 6/28/2025 6:03:28 PM 168
Curiosity — Textbook of Science for Grade 8
9. Match the entries in Column I with those in Column II.
Column I Column II
(i) Concave mirror (a) Spherical mirror with a reflecting
surface that curves inwards.
(ii) Convex mirror (b) It forms an image which is always erect
and diminished in size.
(iii) Convex lens (c) Object placed behind it may appear
inverted at some distance.
(iv) Concave lens (d) Object placed behind it always appears
diminished in size.
10. The following question is based on Assertion/Reason.
Assertion: Convex mirrors are preferred for observing the
traffic behind us.
Reason: Convex mirrors provide a significantly larger view
area than plane mirrors.
Choose the correct option:
(i) Both Assertion and Reason are correct and Reason is the
correct explanation for Assertion.
(ii) Both Assertion and Reason are correct but Reason is not
the correct explanation for Assertion.
(iii) Assertion is correct but Reason is incorrect.
(iv) Both Assertion and Reason are incorrect.
11. In Fig. 10.27, note that O stands for object, M for mirror, and
I for image.
Which of the following statements is true?
(i) Figure (a) indicates a plane mirror and Figure (b)
indicates a concave mirror.
(ii) Figure (a) indicates a convex mirror and Figure (b)
indicates a concave mirror.
(iii) Figure (a) indicates a concave mirror and Figure (b)
indicates a convex mirror.
(iv) Figure (a) indicates a plane mirror and Figure (b)
indicates a convex mirror.

Prepare some questions based on your
learnings so far ...
12. Place a pencil behind a transparent glass tumbler
(Fig. 10.28a). Now fill the tumbler halfway with water
(Fig. 10.28b). How does the pencil appear when viewed
through the water? Explain why its shape appears changed.