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CBSE Worksheet-49

Class VII Science (Light)

1. Bouncing back of light in same medium is called

a. Refraction

b. Reflection

c. Rarefaction

d. Retardation

2. When light bounces off a surface, the surface is

a. Reflector

b. Opaque

c. Transparent

d. Translucent

3. A common magnifying glass is an example of

a. Concave mirror

b. Convex mirror

c. Convex lens

d. Concave lens

4. Shaving mirror are usually

a. Concave

b. Convex

c. Plane

d. Biconcave

5. Match the following

Column A Column B

a. Real image i. Image behind the mirror

b. Virtual ii. Image in front of the mirror

c. Plane mirror iii. Image is same size as object

d. Concave mirror iv. Inverted image

e. Convex mirror v. Erect image

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6. Fill in the blanks

a. Bodies which give out their own light are called -------------.

b. Regular reflection takes place from the --------------- surfaces.

c. --------------- refers to collection of rays.

d. ----------------- mirror is used as rear view mirrors in automobiles.

e. White light is composed of many -----------.

7. How is rainbow formed?

8. What is spectrum?

9. Write the laws of reflection?

10. Write difference between real and virtual image?

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Answer key

1. b

2. a

3. c

4. c

5. (a) (iv), (b) (v), (c) (iii), (d) (ii), (e) (i).

6. (a) luminous bodies(b) smooth(c) Beam (d) Convex (e) colours.

7. Raindrops sometimes act like tiny prisms. They can also scatter sunlight passing

through them into various colours. The combined effect of thousands of raindrops

makes a rainbow.

8. When white rays of light passes through a prism it splits into seven colours. The beam

of light obtain on screen due to scattering is called spectrum.

9. Laws of reflection are

a. The angle of incidence is equal to the angle of reflection.

b. The incident ray, the reflected ray and the normal at the point of incidence all

lies in the same plane.

10.

Real image Virtual image

1. A real image can be obtained on

screen.

1. A virtual image can not be

obtained on screen.

2. It is formed in front of the mirror. 2. It is formed behind the mirror.

3. The reflected rays actually meet

after reflection.

3. The reflected rays do not meet but

appear to come from a point.