21)

Magnification produced by a rear view mirror fitted in vehicles

Class 10 Physics

A)

 is less than one

B)

is more than one

C)

 is equal to one

D)

can be more than or less than one depending upon the position of the object in front of it.

22)

A full length image of a distant tall building can definitely be seen by using

Class 10 Physics

A)

a concave mirror

B)

a convex mirror

C)

a plane mirror

D)

both concave as well as plane mirror

23)

The laws of reflection hold good for

Class 10 Physics

A)

plane mirror only

B)

concave mirror only

C)

convex mirror only

D)

all mirrors irrespective of their shape

24)

When light falls on a smooth polished surface, most of it

Class 10 Physics

A)

is reflected in the same direction

B)

is reflected in different directions

C)

is scattered

D)

 is refracted into the second medium

25)

Focal length of a concave mirror is

Class 10 Physics

A)

negative

B)

positive

C)

depends on the position of object

D)

depends on the position of image

26)

If the power of a lens is – 2 D, what is its focal length?

Class 10 Physics

A)

50 cm

B)

-50 cm

C)

100 cm

D)

-100 cm

27)

The air layer of atmosphere whose temperature is less then the hot layer behave as optically

Class 10 Physics

A)

denser medium

B)

 rarer medium

C)

inactive medium

D)

either denser or rarer medium

28)

Refraction of light by the earth’s atmosphere due to variation in air density is called

Class 10 Physics

A)

 atmospheric reflection

B)

atmospheric dispersion

C)

atmospheric scattering

D)

atmospheric refraction

29)

The deflection of light by minute particles and molecules of the atmosphere in all direction is called ____________ of light.

Class 10 Physics

A)

dispersion

B)

scattering

C)

interference

D)

tyndell effect

30)

One cannot see through the fog, because

Class 10 Physics

A)

refractive index of the fog is very high

B)

light suffers total reflection at droplets

C)

 fog absorbs light

D)

light is scattered by the droplets