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Worksheets

class 8 optics

Total questions: 25

Worksheet time: 31mins

Name
Class
Date
1.

An object which produces its own light is called ………………source

a)

luminous

b)

transparent

c)

non-luminous

d)

opaque

2.

Materials which don’t allow light to pass through them are called…………………

a)

luminous

b)

transparent

c)

non-luminous

d)

opaque

3.

The complete dark region of the shadow is called……………………

a)

penumbra

b)

umbra

c)

translucent

d)

non-luminous

4.

.............. is the perpendicular line to the point where the light strikes the boundary

a)

incident

b)

reflected

c)

refracted

d)

normal

5.

The number of images between two mirrors depends upon

a)

mirror

b)

image

c)

angle

6.

The effect of bending of light is called

a)

reflection

b)

refraction

c)

light

d)

normal

7.

Speed of light in air is …………………. Km/s

a)

300000

b)

200000

c)

250000

d)

100000

8.

When the angle of refraction is 900, the angle of incidence is ...........angle

a)

reflected

b)

refracted

c)

critical

d)

total internal reflection

9.

The angle between the normal and reflected ray is........angle

a)

reflected

b)

refracted

c)

critical

10.

………....occurs when the angle of incidence is greater than the critical angle

a)

total internal reflection

b)

reflection

c)

refraction

d)

none of them

11.

An opaque object is placed in front of a point light source . Which point is on dark area.

a)

K

b)

L

c)

N

d)

O

12.

which of the properties below is not correct for the image in a plane mirror

a)

virtual

b)

the same size as the object

c)

inverted

d)

same distance as the object

13.

which of the following is NOT a colour of the rainbow

a)

yellow

b)

green

c)

red

d)

white

14.

A boy stands 10m in front of a plane mirror then he moves 3m toward the mirror. How many meters does its image moved toward him

a)

20

b)

6

c)

7

d)

14

15.

How many images are formed when the angle between the mirrors is 45 degree.

a)

8

b)

7

c)

6

d)

5

16.

Which letter shows the angle of incidence

a)

a

b)

b

c)

c

d)

d

17.

Which of the figures below is the image of the arrow in a plane mirror

a)
b)
c)
d)
18.

Which of the following is the angle of reflection for the light ray given in the figure

a)

70 degree

b)

60 degree

c)

35 degreee

d)

30 degree

19.

Which letter shows the angle of incidence?

a)

a

b)

b

c)

c

d)

d

20.

Which ray of light shows the correct path of incident light?  ( θ\theta  critical angle= 42 degree)

a)

4

b)

3

c)

2

d)

1

21.

How many images are formed when the angle between mirrors is 450

a)

5

b)

6

c)

7

d)

8

22.

Light travelling from an optically less dense medium into a denser medium bends ............... the normal

a)

away

b)

toward

c)

like

23.

Rough surfaces reflect light in all direction. This reflection is called...............

a)

diffuse

b)

regular

c)

normal

d)

reflection

24.

A girl is standing 75 cm from a flat mirror. What is the distance between the girl and her image?

a)

75 cm

b)

100cm

c)

150 cm

d)

200 cm

25.

A girl is standing 75 cm from the front of a flat mirror. if the girl moves 1 m away from the mirror, what will be the final distance between the girl and her image

a)

150 cm

b)

200 cm

c)

300 cm

d)

350 cm