Solution of Chapter 15. Light (NCERT Science Book)

Exercise

1

Fill in the blanks:

a. An image that cannot be obtained on a screen is called ____________.

b. Image formed by a convex _______ is always virtual and smaller in size.

c. An image formed by a _________ mirror is always of the same size as that of the object.

d. An image which can be obtained on a screen is called a _____ image.

e. An image formed by a concave _______ cannot be obtained on a screen.
2

Mark ‘T’ if the statement is true and ‘F’ if it is false:

a. We can obtain an enlarged and erect image by a convex mirror. (T/F)


b. A concave lens always form a virtual image. (T/F)


c. We can obtain a real, enlarged and inverted image by a concave mirror. (T/F)


d. A real image cannot be obtained on a screen. (T/F).


e. A concave mirror always from a real image. (T/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.
4

State the characteristics of the image formed by a plane mirror.
5

Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.
6

What is a virtual image? Give one situation where a virtual image is formed.
7

State any two differences between a convex and a concave lens.
8

Give one use each of a concave and a convex mirror.
9

Which type of mirror can form a real image?
10

Which type of lens forms always a virtual image?
11

Choose the correct option in question

A virtual image larger than the object can be produced by a


i. concave lens ii. concave mirror


iii. convex mirror iv. Plane mirror.
12

Choose the correct option in question

David is observing his image in a plane mirror. The distance between the mirror and his image is 4m. If he moves 1m towards the mirrors, then the distance between David and his image will be


i. 3m ii. 5m


iii. 6m iv. 8m
13

Choose the correct option in question

The rear-view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear-view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be


i. 1m/s ii. 2m/s


iii. 4m/s iv. 8ms/