NCERT Solutions for Chapter 15 Light Class 7 Science
Book Solutions1
Answer
2
Answer
(b) T
(c) T
(d) F
(e) F
3
Match the items given in Column I with one or more items of Column II.
Column I |
Column II |
(a) A plane mirror |
(i) Used as a magnifying glass. |
(b) A convex mirror |
(ii) Can form image of objects spread over a large area. |
(c) A convex lens |
(iii) Used by dentists to see enlarged image of teeth. |
(d) A concave mirror |
(iv) The image is always inverted and magnified. |
(e) A concave lens |
(v) The image is erect and of the same size as the object. |
- |
(vi) The image is erect and smaller in size than the object. |
Answer
Column I |
Column II |
(a) A plane mirror |
(v) The image is erect and of the same size as the object. |
(b) A convex mirror |
(ii) Can form image of objects spread over a large area. |
(c) A convex lens |
(i) Used as a magnifying glass. |
(d) A concave mirror |
(iii) Used by dentists to see enlarged image of teeth. |
(e) A concave lens |
(vi) The image is erect and smaller in size than the object. |
4
Answer
(i) The image formed is virtual
(ii) The image is laterally inverted.
(iii) It is of the same size as the object.
(iv) The image is situated at the same distance from the mirror as the object.
(v) The image is erected.
5
Answer
Discuss with your classmates to find the same types of words from other languages.
6
Answer
When we stand in front of our dressing table mirror, we use to see our virtual image. The virtual image is formed in case of plane and convex mirror.
7
Answer
Convex lens |
Concave lens |
(i) Convex lens converges the light falling on it. |
(i) Concave lens diverges the light falling on it. |
(ii) Convex lens is thicker in the middle. |
(ii) Concave lens is thinner in the middle. |
8
Answer
Convex mirror forms diminished image therefore it used as rear view mirror in vehicles.
9
Answer
Concave mirror can form a real image.10
Answer
Concave lens forms always a virtual image.11
A virtual image larger than the object can be produced by a
(i) concave lens
(ii) concave mirror
(iii) convex mirror
(iv) plane mirror
Answer
(ii) concave mirror can produce a virtual image larger than the object.12
(i) 3 m
(ii) 5 m
(iii) 6 m
(iv) 8 m
Answer
In case of plane mirror, the image is situated at the same distance from the mirror as the object.
Initial distance between David and the mirror = 4 m
Final distance between David and the mirror = 4-1 = 3 m
Therefore, distance between David and his image = 3+3 = 6m
13
(i) 1 m/s
(ii) 2 m/s
(iii) 4 m/s
(iv) 8 m/s
Answer
In case of plane mirror, the distance is always doubled therefore the speed is in case between the image and the object. So, when driver is reversing his car at a speed of 2 m/s, then the image is also coming closer to the mirror by 2m/s. Thus, it seems that the image of the truck appears to approach the driver at 4 m/s.