A glass sphere appears attractive

Image in the plane mirror is clear

speed of light is constant in all mediums

MCQ Questions for Class 10 Physics Light Reflection And Refraction Quiz 6

Magnification for erect and inverted image is:

0%
$+ve$ and $-ve$ respectively
0%
$-ve$ and $+ve$ respectively
0%
$+ve$
0%
$-ve$

Explanation

Magnification is the ratio of height of image and object.

$m = \dfrac{h_i}{h_o}$

And by convention, height of image formed below principal axis is taken negative and above is taken positive.

Hence,

for erect image, $m=+ve$
for inverted image $m=-ve$ .

Answer is option (A).

Refractive index of diamond with respect to glass is

$1.6$ and absolute refractive index of glass is

$1.5$ . Find out the absolute refractive index of diamond.

0%
$1.06$
0%
$0.93$
0%
$2.4$
0%
$0.75$

Explanation

Given,

Refractive index of diamond with respect to glass,

${ _{ g }{ n }_{ d } } = 1.6$ ,

Absolute refractive index of glass,

$n_{g} = 1.5$

Refractive index of diamond with respect to glass

$= \dfrac {\text {Absolute refractive index of diamond}}{\text {Absolute refractive index of glass}}$

Therefore, absolute refractive index of diamond

$=$ Refractive index of diamond with respect to glass

$\times$ Absolute refractive index of glass

$= 1.6 \times 1.5 = 2.4$

Which of the following comes under laws of refraction?

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Angle of incidence is equal to angle refraction
0%
Angle of refraction is greater than angle of incidence
0%
Value of $\dfrac {sin\ i}{sin\ r}$ is known as refractive index of the medium
0%
All

Explanation

The laws of refraction are as follows:

1. According to the first law of refraction, the incident ray, the refracted ray and the normal to the point of incidence, all lie in the same plane.

2. According to the second law of refraction, also, known as the Snell's law, the ratio of sine of the angle of incidence to the sine of angle of refraction is a constant for a given pair of media.

$\Rightarrow \dfrac{Sin\ i}{Sin\ r} = Constant$

This constant is known as the refractive index.

Hence, the correct answer is option C.

............... lens is known as diverging lens.

0%
Convex
0%
Concave
0%
Sperical
0%
Plano convex

Mark the correct statement

0%
Centre of reflecting surface of a spherical mirror is called the centre of curvature
0%
Pole lies outside the mirror
0%
Pole is represented by Po
0%
None

Transparent medium bounded by two refracting surfaces in which at least one of these is curved is a property of:

0%
Mirror
0%
Lens
0%
Prism
0%
None

A concave mirror produces

$2$ times magnified real image of an object placed at

$5 cm$ in front of it. Where is image located?

0%
$10 cm$
0%
$-5 cm$
0%
$-10 cm$
0%
$2.5 cm$

Explanation

Magnification,

$m = \dfrac {-v}{u}$
Given, magnification,

$m = -2$

$-2 = \dfrac {-v}{-5 cm}$
Therefore, object distance,

$v = -2\times 5 cm = -10 cm$

Mark the correct statement:

0%
Centre of curvature is represented by "C"
0%
Centre of curvature always lies inside the reflecting surface
0%
Centre of curvature always lies in front of mirror
0%
All

Explanation

The reflecting surface of a spherical mirror forms a part of a sphere. The centre of this sphere is called the centre of curvature of the spherical mirror. The Center of curvature can also be defined as the point in the centre of the sphere from which the mirror was sliced. It is represented by the letter

$C$ . Please note that the centre of curvature of the concave mirror lies outside the mirror's reflecting surface. The centre of curvature of a convex mirror behind the mirror.

So, only option-(A) is correct

A concave mirror produces

$10$ times enlarged image (real) of an object placed

$1 cm$ in front of it. Where is the image located?

0%
$5\ cm$
0%
$-10\ cm$
0%
$-5\ cm$
0%
$10\ cm$

Explanation

Given:

$m = -10$ ; magnification

$u = -1$ ; Object distance

$m = \dfrac {-v}{u}$

$\Rightarrow -10 = \dfrac {-v}{-1 }$
Therefore, the image distance,

$v = -10\times 1$

$v = -10\ cm$

Magnification produced by plane mirror is

$+1$ . It means:

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Image formed by plane mirror is greater than size of the object
0%
Image formed by plane mirror is erect and of same size as the object
0%
Image formed by plane mirror is smaller than size of object and is virtual
0%
None

Explanation

Magnification

$= +1$ signifies that the image formed in a plane mirror is of same size as the object. Positive sign in the value of magnification signifies that image formed by a plane mirror is erect.

The focal length of a spherical mirror of radius of curvature

$40 cm$ is

0%
$10 cm$
0%
$20 cm$
0%
$80 cm$
0%
None

Explanation

We know,

$Focal\ length\ (f) = \dfrac{Radius\ of\ curvature\ (R)}{2}$

Given,
Radius of curvature,

$R = 40\ cm$

$\Rightarrow f = \dfrac{R}{2} = \dfrac{40}{2} = 20\ cm$

Hence, the correct answer is OPTION B.

A ray of light travels from air to glass at an angle of incidence of

$37^{\circ}$ , the angle of refraction is

$24^{\circ}$ . What is the refractive index of glass?
(Given:

$\sin 37^{\circ} = 0.60, \sin 24^{\circ} = 0.40)$

0%
$0.66$
0%
$0.133$
0%
$1.5$
0%
None

Explanation

Snell's law states that ratio of sine of angle of incidence to sine of angle of refraction is a constant. This constant is called the refractive index of the medium. Hence:

${ n }_{ ga } = \dfrac {\sin r}{\sin r} = \dfrac {\sin 37^{\circ}}{\sin 24^{\circ}}$

$= \dfrac {0.60}{0.40} = 1.5$

Mark the incorrect statement/statements:

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Centre of curvature is not a part of the mirror
0%
Pole is represented by "Po"
0%
Pole lies outside the mirror
0%
All

An object is placed at a distance of

$100 cm$ from a concave lens of focal length

$40 cm$ . Find the distance of the position of image from the lens in

$cm$ .

0%
$0.035$
0%
$28.57$
0%
$0.015$
0%
None

Explanation

By using sign convention rules
Object distance,

$u = -100\ cm$

Focal length of concave lens,

$f = -40\ cm$

Using lens formula,

$\dfrac{1}{f} = \dfrac{1}{v} - \dfrac{1}{u}$
We have,

$\Rightarrow \dfrac{1}{-40} = \dfrac{1}{v} - \dfrac{1}{-100}$

$\Rightarrow \dfrac{1}{v} = \dfrac{1}{-40} - \dfrac{1}{100}$

$\Rightarrow \dfrac{1}{v} = \dfrac{-100-40}{4000} = \dfrac{-140}{4000} = \dfrac{-7}{200}$

$\Rightarrow v = \dfrac{-200}{7} = -28.57\ cm$

Magnification .

$m=\frac{v}{u}$ =

$\frac{-28.57}{-100}=0.2857$

so magnification positive means virtual image formed.

"- " Indicates virtual image.

A virtual image is formed at a distance of

$28.57\ cm$ from the optical center on the same side of the object.

Hence, the correct answer is OPTION B.

A convex lens of focal length

$5\ cm$ is placed at a distance of

$6\ cm$ from a wall. How far from the lens should an object be placed so as to form its real image on the wall?

0%
$30 cm$
0%
$-30 cm$
0%
$1.2 cm$
0%
$-1.2 cm$

Explanation

Given:

Focal length of lens,

$f = 5cm$

Distance between lens and screen = distance of image formed from the lens

$=v = 6cm$

We know,

$\dfrac {1}{v} - \dfrac {1}{u} = \dfrac {1}{f}$

$\dfrac {1}{6} - \dfrac {1}{u} = \dfrac {1}{5}$

$\dfrac {1}{6} - \dfrac {1}{5} = \dfrac {1}{u}$

$\dfrac {5-6}{30} = \dfrac {1}{u}$

$\dfrac{1}{u} = \dfrac {-1}{30}$

Therefore, the distance of the object from the lens,

$u = -30 cm$ . Or, the object should be placed

$30cm$ far from the lens on the opposite side of the wall.

All distances are measured from the .............. of mirror

0%
Focus
0%
Centre of curvature
0%
Pole
0%
Infinity

The ratio of the sine of angle of incidence to the sine of angle of refraction is a constant for :

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a given pair of media and given colour of light
0%
a given pair of media and any colour of light
0%
any pair of media and given colour of light
0%
any pair of media and any colour of light

Change in the direction of light when it passes from one medium to another is called ............

0%
reflection
0%
refraction
0%
diffraction
0%
scattering

Explanation

$\bf{Reflection}$ is the phenomenon in which light rays on striking a polished surface(such as a mirror) bounce back or are sent back into the same medium.

$\bf{Refraction}$ of light is the phenomenon of bending of light or change in the direction of light, when it passes obliquely from one transparent medium to another.

$\bf{Diffraction}$ is the phenomenon of bending of light waves around the corners of an obstacle or aperture, placed in the path of light beam.

$\bf{Scattering}$ is the phenomenon by which a beam of light is redirected or deflected in many different directions when it passes through an imperfect medium due to the interaction with the particles of the medium.

Hence, the correct answer is OPTION B.

Centre of curvature of a concave mirror lies .......

0%
Behind it
0%
In front of it
0%
In its centre
0%
None

The curved surface of a shining spoon could be considered as a ...............

0%
Curved mirror
0%
Plane mirror
0%
Concave mirror only
0%
None

When a ray of light passes through a rectangular slab, made up of some transparent material other than glass, the emergent ray is

0%
Parallel to the incident ray produced
0%
Perpendicular to the incident ray produced
0%
Oblique to the incident ray produced
0%
Inclined to the incident ray produced

When light travels from air to water there is ...........................

0%
Reflection of light
0%
Refraction of light
0%
Diffraction of light
0%
Scattering of light

Explanation

$\bf{Reflection}$ is the phenomenon in which light rays striking a polished surface(such as a mirror) bounce back or are sent back into the same medium.

$\bf{Refraction}$ of light is the phenomenon of bending of light or change in the direction of light when it passes obliquely from one transparent medium to another.

$\bf{Diffraction}$ is the phenomenon of bending of light waves around the corners of an obstacle or aperture placed in the path of the light beam.

Due to refraction,

0%
Image in the plane mirror is clear
0%
Polished black surfaces shine
0%
speed of light is constant in all mediums
0%
A glass sphere appears attractive

Laws of refraction to hold good:

0%
one medium has to be air
0%
one medium has to be glass
0%
one medium has to be solid
0%
two media should have different optical densities

The surface of the spoon which is curved inwards can be approximated to be (

$a$ ) .......... mirror and the surface of the spoon which is bulged outwards can be approximated to (

$b$ ) ......... mirror.

0%
$(a) = convex, (b) = concave$
0%
$(a) = concave, (b) = convex$
0%
$(a) = convexo \ convex, (b) = concavo \ concave$
0%
$(a) = concavo \ canvex, (b) = convexo \ concave$

Explanation

$\bf{Convex\ Mirror}$ is a curved mirror where the reflective surface bulges out, towards the light source.

$\bf{Concave\ Mirror}$ is a curved mirror where the reflective surface is curved inwards.

Therefore, the surface of the spoon which is curved inwards can be approximated to be Concave mirror.
The surface of the spoon which is bulged outwards can be approximated to be Convex mirror.

Hence, the correct answer is OPTION B.

The centre of the sphere from which the spherical mirror has been formed is called ....................

0%
Pole
0%
Centre of curvature
0%
Focus
0%
None

Explanation

The reflecting surface of a spherical mirror is a part of a sphere. The centre of the sphere is called the centre of curvature of the spherical mirror. It is represented by the letter

$C$ .

Hence option B is correct

For a light ray undergoing refraction,

$\dfrac{sin i}{sin r}=$

0%
$\frac{\mu_2}{\mu_1}$
0%
$1$ , always
0%
$0$ , always
0%
none of these

Explanation

According to Snell's law of refraction,

$\mu_1sini=\mu_2sinr$

$\frac{sini}{sinr}=\frac{\mu_2}{\mu_1}$

Where

$\mu_1$ and

$\mu_2$ are refractive index of first and second medium respectively.

The incident ray, the normal at the point of incidence and the refracted ray:

0%
lie on mutually orthogonal planes
0%
lie on mutually parallel planes
0%
lie on the same plane
0%
lie on different arbitrary planes

The cut part of sphere is coated outside with silver or similar material. What kind of mirror does it form?

0%
Convex mirror
0%
Concave mirror
0%
Plane mirror
0%
None

Fill in the blank:

Focal length (

$f$ ) is the distance of principal focus from ______ of mirror.

0%
Centre of curvature
0%
Focus principal (F)
0%
Pole (P)
0%
None

Explanation

Focal length

$f$ is the distance of principal focus from the pole of mirror.

A concave mirror always form a real image. This statement is:

0%
True
0%
False

What is the difference between concave and convex mirrors? Choose the correct statement ?

0%
Convex mirror is curved outwards and concave mirror is curved inwards
0%
Focal point is in front of convex mirror and for a concave mirror, it is behind
0%
Centre of curvature is in front of convex mirror and for a concave mirror, it is behind
0%
None of these

When a ray of light passes through the rectangular glass slab, the angle of deviation is

0%
equal to $0$
0%
an acute angle
0%
an obtuse angle
0%
equal to $\dfrac{\pi}{2}$

Explanation

When a ray of light passes through a rectangular glass slab, the emergent ray is parallel to the incident ray produced.
Now, angle of deviation is the angle between the emergent ray and the incident ray produced.
So, these two rays being parallel, the angle of deviation is

$0$ .

When a ray of light passes through a rectangular glass slab:

0%
After the first refraction, it bends towards the normal and after the second refraction it bends away from the normal
0%
After the first refraction, it bends away from the normal and after the second refraction it bends towards the normal
0%
After both refractions, it bends towards the normal
0%
After both refractions, it bends away from the normal

Fill in the blanks:

________ is geometric centre of spherical mirror.

0%
Principal force (F)
0%
Centre of curvature (C)
0%
Pole (P)
0%
Secondary focus $(F_2)$

A ray of light passes through a glass slab and the angle of emergence is found to be smaller than the angle of incidence. So, we may conclude that the glass slab

0%
Is rectangular in shape
0%
Is square in shape
0%
Is not rectangular or square in shape
0%
May or may not be rectangular in shape

A man focused an inverted image formed by a lens. It can be:

0%
Convex lens
0%
Concave lens
0%
Convex or concave lens
0%
Plane mirror

Principal axis is the line joining the pole and the:

0%
Principal line
0%
Centre of curvature
0%
Mirror
0%
None of these

The primary phenomenon in the working of lens is

0%
Reflection
0%
Refraction
0%
Scattering
0%
Diffusion

Which of the following is included in laws of refraction?

0%
$\dfrac{sin \ i}{sin\ r}=\mu$
0%
The incident ray, the refracted ray and normal at the point of incidence all lie in the same plane
0%
$\angle \ i=\angle\ r$ , where $r$ is angle of refraction
0%
$\angle \ i<\angle\ r$ , where $r$ is angle of refraction

To find the trace of light in a glass slab using pins, minimum number of pins required are

0%
2
0%
3
0%
4
0%
6

Occurrence of mirage in deserts in summer is an example of ..........................

0%
reflection of light
0%
refraction of light
0%
propagation of sound
0%
conduction of heat

A straight line passing through the two centres of curvature of lens is called:

0%
Normal
0%
Principal axis
0%
Centre axis
0%
Diameter axis

In the given figure, diameter of lens equals:

0%
$FO$
0%
$2FO$
0%
$3FO$
0%
$4FO$

Explanation

Focal length,

$f=FO = \dfrac{radius}{2}$

Diameter =

$2 \times radius$

Diameter

$= 4 FO$

A reflecting surface which is a part of a sphere is called:

0%
concave mirror
0%
convex mirror
0%
spherical mirror
0%
all of these

The refractive index of a medium is ______ to the speed of light in the medium.

0%
directly proprtional
0%
inversely proportional
0%
independent
0%
exponentially increasing

According to laws of refraction, refraction of light at the boundary between two different regions follow:

0%
that the incident ray, the normal at the point of incidence and the refracted ray, all lie in the same plane.
0%
that for a given pair of media and given colour of light, the ratio of the sine of angle of incidence to the sine of angle of refraction is constant.
0%
both A and B
0%
neither A nor B

Explanation

Refraction of light obeys the following two laws:

1. The incident ray, the normal at the point of incidence and the refracted ray, all lie in the same plane.

2. For a given pair of media and given the colour of light, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.

The second postulate is also known as Snell's Law which is as:

$\dfrac{sini}{sinr}=\dfrac{n_2}{n_1}$ =

$constant$

_______ lens is thickest in the middle and ________ lens is thinnest at the middle

0%
Concave, Convex
0%
Convex, Concave
0%
Convex, Plane
0%
Convex, Convex

The refractive index of a medium:

0%
is defined with respect to another medium
0%
is an absolute constant for a medium
0%
depends on the frequency of the light in the medium
0%
is more for higher intensity of light ray

Given a trace of light, refractive index of the medium can be found by using:

0%
universal Law of light
0%
Shell's Law
0%
Snell's Law
0%
Hooke's Law

Explanation

According to Snell's Law,

$\mu = \dfrac{sin\ i}{sin\ r}$

where

$\mu: \text{Refractive index of the medium 2 w.r.t. medium 1}$

$i: \text{Angle of incidence}$

$r: \text{Angle of refraction}$

If trace of light is known, then

$i$ and

$r$ are known and hence

$\mu$ can be found.

CBSE Questions for Class 10 Physics Light Reflection And Refraction Quiz 6 - MCQExams.com

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Practice Class 10 Physics Quiz Questions and Answers

CBSE Questions for Class 10 Physics Light Reflection And Refraction Quiz 6 - MCQExams.com

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Practice Class 10 Physics Quiz Questions and Answers

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