Light Reflection and Refraction Test

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Light Reflection and Refraction Test - 45

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Question 1
1 / -0

The term refraction of light is best described by:

A
The bending of light rays when they enter from one medium to another medium

B
Splitting of white light into seven colours when it passes through the prism

C
Bending of light round corners of obstacles and apertures

D
Coming back of light from a bright smooth surface

Solution

When light enters from one medium to another, its speed and direction changes. This phenomenon of bending of light rays while going from one medium to another is called refraction.
Question 2
1 / -0

The focal length of a concave mirror depends on:

A
The radius of curvature of the mirror

B
The object distance from the mirror

C
The image distance from the mirror

D
Both the image and the object distance

Solution

For any spherical mirror, the focal length $$f$$ is equal to half of the radius of curvature$$R$$.
$$f=\dfrac{R}{2}$$
So, the focal length of a concave mirror depends upon the radius of curvature of the mirror.
Question 3
1 / -0

The magnification produced by a concave mirror:

A
is always more than one

B
is always less than one

C
is always equal to one

D
may be less than, equal to or greater than one

Solution

A concave mirror can form following types of images;

1. Real and diminished when object is kept beyond radius of curvature so, $$m$$ is negative and $$0<|m|<1$$.

2. Virtual and enlarged when the object is kept between focus and the pole so, $$m$$ is positive and $$|m|>1$$.

3. Real and enlarged when the object is kept between focus and radius of curvature so, $$m$$ is negative and $$|m|>1$$

4. Real and of same size when the object is kept on the radius of curvature so, $$m = -1$$.
Question 4
1 / -0

Twinkling of stars is due to

A
variation of refractive index in the earth's atmosphere

B
the fact that light is not emitted by the stars continuously

C
the absorption oflight by earth's atmosphere

D
none of these

Solution

The twinkling of stars is due to atmospheric refraction of star-light. The refraction of light caused by the earth's atmosphere having air layers of varying optical density is called atmospheric refraction.
The physical conditions of the atmosphere keep on changing continuously due to which density of air in different layers of atmosphere also keeps on changing.
As a result of this, the refractive index of the various layers of atmosphere also keeps on changing continuously. So, light coming from stars suffers multiple refraction and the amount of starlight reaching the eye also keeps changing and so, due to fluctuation of perceived brightness of the star, they appear like they are twinkling.

Hence, the correct answer is OPTION A.
Question 5
1 / -0

The image of our face in a plane mirror is :

A
real

B
magnified

C
diminished

D
virtual

Solution

For a plane mirror the image formed is behind the mirror, so by definition its virtual
Question 6
1 / -0

The radius of curvature of a plane mirror is:

A
zero

B
infinite

C
negative

D
finite

Solution

A plane mirror may be considered to be a part of an infinitely large spherical surface.
And, an infinitely large spherical surface will have infinite radius.
So, radius of curvature for a plane mirror will be infinite.
Question 7
1 / -0

A mirage occurs because

A
The refractive index of atmosphere increases with height

B
The refractive index of atmosphere decreases with height

C
The hot ground acts like a mirror

D
Refractive index remains constant with height

Solution

$$Answer:-$$ A
As hot air rises above cold air descends so as we move upward refractive index also decreases .
For exhausted travelers in the desert, an inferior mirage may appear to be a lake of water in the distance. An inferior mirage is called "inferior" because the mirage is located under the real object. The real object in an inferior mirage is the (blue) sky or any distant (therefore bluish) object in that same direction. The mirage causes the observer to see a bright and bluish patch on the ground in the distance.
Light rays coming from a particular distant object all travel through nearly the same air layers and all are bent over about the same amount. Therefore, rays coming from the top of the object will arrive lower than those from the bottom. The image usually is upside down, enhancing the illusion that the sky image seen in the distance is really a water or oil puddle acting as a mirror.
Question 8
1 / -0

Twinkling of stars is on account of

A
Large distance of stars and storms in air

B
Small size of stars

C
Large size of stars

D
Large distance of stars and fluctuations in the density of air

Solution

Answer:− D
In simple terms, the twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Twinkling effects are caused by anomalous refraction caused by small-scale fluctuations in air density usually related to temperature gradients
Question 9
1 / -0

The ratio of the size of the image to the size of the object is known as :

A
The Focal Plane

B
The Transformation ratio

C
The Efficiency

D
The Magnification ratio

Solution

Ratio of the size of the image to the size of object is known as the Magnification ratio. It is given as:

$$m = \dfrac{v}{u}$$
Question 10
1 / -0

The principal axis is also called _______ of the lens.

A
optical axis

B
x-axis

C
y-axis

D
axis

Solution

The principal axis is also called optical axis of a lens as it passes through the optical centre of the lens.

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Re-Attempt Weekly Quiz Competition

Light Reflection and Refraction Test - 45

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Light Reflection and Refraction Test - 45

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SHARING IS CARING

Question 1

The bending of light rays when they enter from one medium to another medium

Splitting of white light into seven colours when it passes through the prism

Bending of light round corners of obstacles and apertures

Coming back of light from a bright smooth surface

Solution

Question 2

The radius of curvature of the mirror

The object distance from the mirror

The image distance from the mirror

Both the image and the object distance

Solution

Question 3

is always more than one

is always less than one

is always equal to one

may be less than, equal to or greater than one

Solution

Question 4

variation of refractive index in the earth's atmosphere

the fact that light is not emitted by the stars continuously

the absorption oflight by earth's atmosphere

none of these

Solution

Question 5

real

magnified

diminished

virtual

Solution

Question 6

zero

infinite

negative

finite

Solution

Question 7

The refractive index of atmosphere increases with height

The refractive index of atmosphere decreases with height

The hot ground acts like a mirror

Refractive index remains constant with height

Solution

Question 8

Large distance of stars and storms in air

Small size of stars

Large size of stars

Large distance of stars and fluctuations in the density of air

Solution

Question 9

The Focal Plane

The Transformation ratio

The Efficiency

The Magnification ratio

Solution

Question 10

optical axis

x-axis

y-axis

axis

Solution

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