CBSE Questions for Class 10 Physics Light Reflection And Refraction Quiz 3 - MCQExams.com

What is the distance $$PA$$ called?
202641_a0491aaf69664d3c90f843e9b8e3ff5e.png
  • Equivalent distance
  • Equivalent radius
  • Radius of curvature
  • Center of curvature
A ray of light travelling in air is incident on the plane of a transparent medium. The angle of incident is $$45^0$$ and that of refraction is $$30^0$$. The refractive index of the medium with respect to air is:
  • $$2$$
  • $$\dfrac {1}{\sqrt 2}$$
  • $$2\sqrt 2$$
  • $$\sqrt 2$$
Find the refractive index of glass with respect to water. The refractive indices of glass and air with respect to air are $$3/2$$ and $$4/3$$ respectively.
  • $$2/1$$
  • $$1/2$$
  • $$9/8$$
  • $$8/9$$
In case of a virtual and erect image, the magnification of a mirror is :
  • Positive
  • Negative
  • Unity
  • Infinity
If the magnification of a body of size 1 m is 2, what is the size of the image?
  • 1m
  • 2m
  • 3m
  • 4m
Formula of focal length in convex lens is
  • $$\displaystyle f = \frac{u+v}{u-v}$$
  • $$\displaystyle f = \frac{u\times v}{u-v}$$
  • $$\displaystyle f = \frac{u-v}{u+v}$$
  • $$\displaystyle f = \frac{u+v}{u+v}$$
A light ray passing from crown glass to flint glass, then the speed of light is:
  • smaller in crown glass than in flint glass
  • larger in crown glass than in flint glass
  • same in crown glass and  in flint glass
  • zero in crown glass and flint glass
The rays parallel and close to the principal axis are called:
  • Converging rays
  • Diverging rays
  • Coherent rays
  • Paraxial rays
Ratio of the size of the image to the size of the object is known as:
  • Focal plane
  • Transformation ratio
  • Efficiency
  • Magnification
The distance between the extreme points on the periphery of the mirror is called:
  • focal length
  • radius of curvature
  • principal section
  • none of these
The centre of curvature of a ______ mirror lies behind the mirror.
  • Convex
  • Concave
  • Both $$A$$ and $$B$$
  • None of these
The central point of a spherical mirror is called:
  • Pole
  • Centre of sphere
  • Centre of curvature
  • None of these
The unit of magnification is:
  • m
  • $$m^2$$
  • $$m^{-1}$$
  • None of these
The bending of light as it passes from one medium into another is commonly known as
  • Reflection
  • Refraction
  • Scattering
  • Dispersion
Two points such that each focus for the rays proceedings from the other, are called :
  • Centres of curvature
  • Conjugate foci
  • Converging foci
  • None of these
The angle which subtends the periphery of the spherical mirror at the centre of curvature is called:
  • angular aperture
  • glancing angle
  • critical angle
  • none of these
The centre of curvature of a ___________ mirror is in front of it.
  • convex
  • concave
  • convex or concave
  • none of these
Which of the following quantity does not have any unit?
  • Velocity of light
  • Light year
  • Magnification
  • Power of a lens
In a concave mirror, an object is placed a distance $$d_1$$ from the focus and the real image is formed at a distance $$d_2$$ from the focus. Then the focal length of the mirror is
  • $$\sqrt {d_1d_2}$$
  • $$d_1d_2$$
  • $$\frac {d_1d_2}{2}$$
  • $$\sqrt {d_1/d_2}$$
A glass slab is placed in the path of a beam of convergent light; the point of convergence of light
  • Moves towards the glass slab
  • Moves away from the glass slab
  • Remains at the same point
  • Undergoes a lateral shift
A lens which is thinner at the middle and thicker at the edges is called a :
  • Convex lens
  • Concave lens
  • Cylindrical lens
  • None of these
The focal length of a lens is 0.1 m. Then the lens must be :
  • Convex
  • Concave
  • Cylindrical
  • None of these
An object is placed on the principal axis of a concave mirror at a distance of $$60\ cm$$. If the focal length of the concave mirror is $$40\ cm$$ then the magnification obtained is equal to:
  • $$-2$$
  • $$-1.5$$
  • $$-3$$
  • $$-1$$
A lens which is thicker in the middle and thinner at the edges is called a :
  • Convex lens
  • Concave lens
  • Cylindrical lens
  • None of these
The expression for the magnification of a spherical mirror in the terms of focal length (f) and the distance of the object from mirror (u) is
  • $$\frac{-f}{u-f}$$
  • $$\frac{f}{u+f}$$
  • $$\frac{-f}{u+f}$$
  • $$\frac{f}{u-f}$$
The constant ratio of the sine of angle of incidence to the sine of angle of refraction is also known as:
  • Snell's law
  • Optical density
  • Relative density
  • None of these
When light travels from one medium into another it suffers
  • Reflection
  • Refraction
  • Dispersion
  • None of these
A ray of light is incident on a medium with angle of incidence i and refracted into a second medium with angle of refraction $$r$$. The graph of $$\sin(i)$$ Vs $$\sin(r)$$ is as shown in the figure. Then the velocity of light in the first medium is ................. times the velocity of light in the second medium.
126826_acbe52ea80d2461c897d0003523fbc4f.png
  • $$\sqrt{3}$$
  • $$1/\sqrt{3}$$
  • $$\sqrt{3}/2$$
  • $$2/\sqrt{3}$$
Ram and Shyam observe a virtual image formed by a real object placed a distance $$\dfrac{f}{2}$$ in front of a convex lens of focal length $$f$$. Now they want to use a concave lens having a focal length f so that a virtual image is formed at the same distance from the lens as before. Where should the object be kept relative to the concave lens
  • The object should be at innity
  • Object should be at a distance of $$f$$
  • Object should be at $$f/2$$
  • Object should be at $$2f$$
Fig shows an object and its image formed by a thin lens. Then the nature and focal length of lens is

159966_9aa834b7fa1f45968469e5c2226d7d5d.png
  • $$f=4.8$$ cm converging lens
  • $$f=-4.8$$ cm diverging lens
  • $$f=2.18$$ cm converging lens
  • $$f=-2.18$$ cm diverging lens
If an object is placed at a distance of 20cm from the pole of a concave mirror, the magnification of its real image isIf  the object is moved away from the mirror by 10cm, then the magnification is -1.
  • True
  • False
The image formed by a plane mirror may be -
  • Real
  • Virtual
  • Larger
  • None of above
A convex lens forms an image of an object placed $$20 cm$$ away from it at a distance of $$20 cm$$ on the other side of the lens. If the object moves $$5 cm$$ towards the lens, then the image will be :
  • $$5 cm$$ toward the lens
  • $$5 cm$$ away from the lens
  • $$10 cm$$ toward the lens
  • $$10 cm$$ away from the lens
A converging beam of rays is incident on a diverging thin lens. Having passed through the lens the ray intersect at a point 15 cm from the lens. If lens is removed the point where the rays meet will move 5 cm closer towards the mounting that holds the lens. The focal length of lens is
  • $$f=10 cm$$
  • $$f=15 cm$$
  • $$f=30 cm$$
  • $$f=40 cm$$
The cause of mirage formation in desert areas is
  • The refractive index of atmosphere decreases with decrease in height
  • The refractive index of atmosphere increases with decrease in height
  • The refractive index of atmosphere does not change with height
  • Scattering
Which of the following (referred to a spherical mirror) do (does) not depend on whether the rays are paraxial or not?
  • Pole
  • Focus
  • Radius of curvature
  • Principal axis
If the light moving in a straight line bends by small but fixed angle while entering in different medium , it may be a case of :
  • reflection of light
  • refraction of light 
  • scattering of light
  • dispersion of light
Light is incident on a glass block as shown in Fig. If $$\theta_{1}$$ is increased slightly, what happens to $$\theta_{2}$$?
159180_670cb6eaaa704aa7bf3e16326e4c2aa1.png
  • $$\theta_{2}$$ also increases slightly
  • $$\theta_{2}$$ is unchanged
  • $$\theta_{2}$$ decreases slightly
  • $$\theta_{2}$$ changes abruptly, since the ray experience total internal reflection
An object kept on the principal axis and infront of a spherical mirror, is moved along the axis itself. Its lateral magnification m is measured, and plotted versus object distance |u| for a range of u, as shown in fig. The magnification of the object when it is placed at a distance 20 cm in front of the mirror is:

159926_53a63f600d3f4c51a9d237bea33fbd59.png
  • $$-1$$
  • $$1$$
  • $$8$$
  • $$20$$
An object is kept at $$15\ cm$$ from a convex mirror of focal length $$25\ cm$$. What is the magnification?
  • $$4/9$$
  • $$5/8$$
  • $$9/4$$
  • $$8/5$$
A ray of light is incident on a medium with angle of incidence $$i$$ and refracted into a second medium with angle of refraction $$r$$. The graph of $$sin(i)\ vs\ sin(r)$$ is as shown in fig. Then, the velocity of light in the first medium in $$n$$ times the velocity of light in the second medium. What should be the value of $$n$$?

157776_7f974fb2ddaf4081814948854c99ad3a.png
  • $$\sqrt {3}$$
  • $$1/\sqrt {3}$$
  • $$\sqrt {3}/2$$
  • $$2/\sqrt {3}$$
The diagram alongside shows the refraction of a ray of light from air to a liquid. The refractive index of liquid with respect to air is :
181696_dce5ae58430d47e39859e609e6c303f9.png
  • $$\sqrt{\dfrac{1}{_{\displaystyle 2}}}$$
  • $$\sqrt{\dfrac{2}{_{\displaystyle 3}}}$$
  • $$\sqrt{\dfrac{3}{_{\displaystyle 2}}}$$
  • $$\sqrt{3}$$
Find the magnification and nature of the image when point $$O$$ is $$30\ cm$$ behind the mirror.
  • $$2$$ (Virtual, Inverted)
  • $$3$$ (Real, Inverted)
  • $$5$$ (Real, Erect)
  • $$2$$ (Virtual, Erect)
A beam of light converges towards a point O, behind a convex mirror of focal length 20 cm. Find the magnification and nature of the image when point O is 30 cm behind the mirror.
  • 2 (virtual, inverted)
  • 3 (real, inverted)
  • 3, (virtual, enlarged)
  • +1 (real, enlarged)
The diagram alongside shows the refraction of a ray of light from air to a liquid. Angle of incidence is :
181636_81b9b4dfce2246be8e6dfbf22e0ede97.png
  • $$30^o$$
  • $$45^o$$
  • $$90^o$$
  • $$60^o$$
The diagram alongside shows the refraction of a ray of light from air to a liquid. Angle of refraction is:
181690_243df318a3d3480083af7a4c05d5fa80.png
  • $$60^o$$
  • $$15^o$$
  • $$30^o$$
  • $$45^o$$
The incident ray, the _______ ray and the normal lie in the same plane during refraction.
  • reflected
  • refracted
  • diffused
  • blocked
In the given figure, name the ray which represents the correct path of light while emerging out through a glass blocks :
181721_67f00e71afcc409588669b81946dfe70.png
  • $$A$$
  • $$B$$
  • $$C$$
  • $$D$$
A ray of light from air suffers partial reflection and refraction at the boundary of water as shown in the figure. In Fig, which of the ray is the correct refracted ray?
181630_d213cb74221b4c8c9d40b49f594bbb0c.png
  • $$A$$
  • $$B$$
  • $$C$$
  • $$D$$
A ray of light is incident at the glass-water interface at an angle i. It merges finally parallel to the surface of water. Then, the value of $$\mu_g$$ would be :

161981_fe9fd9e5a7194903b4a2c35454664328.png
  • $$(4/3) sin i$$
  • $$1/ sin i$$
  • $$4/3$$
  • $$1$$
0:0:1


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