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Worksheetsclass 8 optics
Total questions: 25
Worksheet time: 31mins
An object which produces its own light is called ………………source
luminous
transparent
non-luminous
opaque
Materials which don’t allow light to pass through them are called…………………
luminous
transparent
non-luminous
opaque
The complete dark region of the shadow is called……………………
penumbra
umbra
translucent
non-luminous
.............. is the perpendicular line to the point where the light strikes the boundary
incident
reflected
refracted
normal
The number of images between two mirrors depends upon
mirror
image
angle
The effect of bending of light is called
reflection
refraction
light
normal
Speed of light in air is …………………. Km/s
300000
200000
250000
100000
When the angle of refraction is 900, the angle of incidence is ...........angle
reflected
refracted
critical
total internal reflection
The angle between the normal and reflected ray is........angle
reflected
refracted
critical
………....occurs when the angle of incidence is greater than the critical angle
total internal reflection
reflection
refraction
none of them
An opaque object is placed in front of a point light source . Which point is on dark area.
K
L
N
O
which of the properties below is not correct for the image in a plane mirror
virtual
the same size as the object
inverted
same distance as the object
which of the following is NOT a colour of the rainbow
yellow
green
red
white
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
20
6
7
14
How many images are formed when the angle between the mirrors is 45 degree.
8
7
6
5
Which letter shows the angle of incidence
a
b
c
d
Which of the figures below is the image of the arrow in a plane mirror
Which of the following is the angle of reflection for the light ray given in the figure
70 degree
60 degree
35 degreee
30 degree
Which letter shows the angle of incidence?
a
b
c
d
Which ray of light shows the correct path of incident light? ( θ critical angle= 42 degree)
4
3
2
1
How many images are formed when the angle between mirrors is 450
5
6
7
8
Light travelling from an optically less dense medium into a denser medium bends ............... the normal
away
toward
like
Rough surfaces reflect light in all direction. This reflection is called...............
diffuse
regular
normal
reflection
A girl is standing 75 cm from a flat mirror. What is the distance between the girl and her image?
75 cm
100cm
150 cm
200 cm
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
150 cm
200 cm
300 cm
350 cm
