CBSE Questions for Class 12 Medical Physics Ray Optics And Optical Instruments Quiz 12 - MCQExams.com

A ray of light enters a spherical drop of water of refractive index $$\mu$$ as shown in fig. An expression of the angle between incident ray and emergent ray (angle of deviation) as shown in fig. is :

160965_69289bee9a834339826ef6d0f0436418.png
  • $$0^{\circ}$$
  • $$\phi$$
  • $$\alpha -\phi$$
  • $$\pi - 4\alpha + 2\phi$$
Which of the following are defects of vision?
  • Myopia
  • Hypermetropia
  • Colour blindness
  • Night blindness
A man can see objects clearly up to $$3 m$$. What type of lens he should use in order to see clearly up to $$12 m$$?
  • Convex lens, $$f= 4 m$$
  • Concave lens, $$f= 4 m$$
  • Convex lens, $$f= -4 m$$
  • Concave lens, $$f= -4 m$$

Three identical isosceles right-angled prism (ABC, BCD and CDE) are placed as shown in the figure $$\displaystyle \angle ABC,\angle BCD\, and\, \angle CDE$$ are $$\displaystyle 90^{\circ}$$ in the given prism respectively. A ray is incident along line AB Refraction takes placed at BC and CD and then it emerges along the line DE $$\displaystyle \mu _{1},\mu _{2}$$ and $$\displaystyle \mu _{3}$$ are the refractive index of prism ABC, BCD and CDE respectively. The relation between $$\displaystyle \mu _{1},\mu _{2}\,and\,\mu _{3}$$ is
332952_6cec26f03b154000b12898a8805dfcf3.png
  • $$\displaystyle \mu _{2}^{2}+\mu _{1}^{2}-\mu _{2}^{3}+2=0$$
  • $$\displaystyle \mu _{2}^{2}-\mu _{1}^{2}-\mu _{3}^{2}+2=0$$
  • $$\displaystyle \mu _{2}^{2}+\mu _{1}^{2}-2\mu _{3}^{2}+2=0$$
  • $$\displaystyle \mu _{2}^{2}-\mu _{1}^{2}-5\mu _{3}^{2}+2=0$$
A spherical lens has a focal length $$2\ cm$$. The lens will be
  • Concave lens
  • Convex lens
  • Concavo convex lens
  • None
As shown in figure, the liquids $$L_1,L_2$$ and $$L_3$$ have refractive indices. $$1.55,\ 1.50$$ and $$1.20$$ respectively. Therefore, the arrangement corresponds to 
1139594_5b47627149d54cfba875dc465ff2fd1e.png
  • biconvex lens
  • biconcave lens
  • concavo-convex lens
  • convexo-concave lens
There is an equiconvex lens of focal length of $$20   cm$$. If the lens is cut into tow equal parts perpendicular to the optical axis, the focal length of each part will be
  • 20 cm
  • 10 cm
  • 40 cm
  • 15 cm
The ratio of $$\frac {\theta _1}{\theta _2}$$ is.
333372_9ffa46446c3b47b581a220331aefb88e.png
  • 1
  • $$\frac {1}{2}$$
  • $$\sqrt 2$$
  • $$\frac {1}{\sqrt 2}$$
The total deviation of the incident ray when it emerges out of the prism is.
333377_805377e33e04494c8b30c08e9d01b599.png
  • $$30^o$$
  • $$60^o$$
  • $$90^o$$
  • $$45^o$$
A man can see distinctly from a distance of $$0.5 m$$. If he wants to read a book placed at a distance of $$25 cm$$, then what kind of lens should he use?
  • Convex lens with focal length of $$-50 cm$$
  • Concave lens with focal length of $$-50 cm$$
  • Convex lens with focal length of $$50 cm$$
  • Concave lens with focal length of $$50 cm$$
The process of re-emission of absorbed light in all directions with different intensities by the atom or molecule is called ____________.
  • Scattering of light
  • Dispersion of light
  • Reflection of light
  • Refraction of light
Magnification of lens is:
  • $$\dfrac {\text {Size of the image}}{\text {Size of the object}}$$
  • $$\dfrac {\text {Image distance}}{\text {Object distance}}$$
  • Both A and B
  • None
A ray of light traveling in the air is incident on the plane of a transparent medium. The angle of the incident is 45$$^o$$ and that of refraction is 30$$^o$$. Find the refractive index of the medium.
  • 2
  • $$\dfrac{1}{\sqrt 2}$$
  • $$2 \sqrt 2$$
  • $$\sqrt 2$$
a diverging lens of focal length - $$10$$ cm is moving towards right with a velocity $$5$$ m/s. An object, placed on Principal axis is moving towards left with a velocity $$3$$ m/s. The velocity of the image at the instant when the lateral magnification produced is $$1/2$$ is: (All velocities are with respect to ground) 
  • $$3$$ m/s towards right
  • $$3$$ m/s towards left
  • $$7$$ m/s towards right
  • $$7$$ m/s towards left
Two glass prisms $$P_1$$ and $$P_2$$ are to be combined together to produce dispersion without deviation. The angles of the prisms $$P_1$$ and $$P_2$$ are selected as $$4^o$$ and $$3^o$$ respectively. If the refractive index of prism $$P_1$$ is 1.54, then that of $$P_2$$ will be
  • 1.48
  • 1.58
  • 1.62
  • 1.72
A rectangular block is composed of three different glass prisms (with refractive indices $$\mu_1, \mu_2$$ and $$\mu_3$$) as shown in the figure below. A ray of light incident to the left face emerges normal to the right face. Then the refractive indices are related as:
734166_b48a356c5d1740fbb979531d5e64c910.png
  • $$\mu_1^2 + \mu_2^2 = 2 \mu_3^2$$
  • $$\mu_1^2 + \mu_2^2 = \mu_3^2$$
  • $$\mu_1^2 + \mu_3^2 = 2 \mu_2^2$$
  • $$\mu_2^2 + \mu_3^2 = 2 \mu_1^2$$
A vessel is filled with oil as shown in the diagram. A ray of light from point $$O$$ at the bottom of vessel is incident on the oil - air interface at point $$P$$ and grazes the surface along $$PQ$$. The refractive index of the oil is close to-
721061_8e64fec1139040fbae5b7fa56c0d60c4.png
  • $$1.41$$
  • $$1.50$$
  • $$1.630$$
  • $$1.73$$
In Section A, defects of eye are given, in Section B, effects arising due to defects are given and in section C, remedies are given using lenses. Find the correct pair.
Section A
Section B
Section C
Myopia
(x) Focal length increases
(a) Bifocal lens
Hypermetropia
(y)Focal length decreases
(b) Concave lens
Presbyopia
(z) Power of accommodation decreases
(c) Convex lens
  • (1 - y - b), (2 - x - c), (3 - z - a)
  • (1 - z - b), (2 - z - b), (3 - y - b)
  • (1 - x - a), (2 - y - c), (3 - x - a)
  • (1 - y - a), (2 - x - a), (3 - z - c)
Figure shows an irregular block of material of refractive index $$\sqrt { 2 }$$. A ray of light strikes the face $$AB$$ as shown in figure. After refraction, it is incident on a spherical surface $$CD$$ of radius of curvature $$0.4 m$$ and enters a medium of refractive index $$1.514$$ to meet $$PQ$$ at $$E$$. Find the distance $$OE$$ upto two places of decimal :
670008_d84f88f1158c488eb25118d94b360ae5.jpg
  • $$7 m$$
  • $$.29 m$$
  • $$6.06 m$$
  • $$8.55 m$$
A man is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the sun is $$ 1.39 \times 10^9 m$$ and its mean distance from the earth is $$1.5 \times 10^{11} \ m$$, the diameter of the sun's image on the paper is 
  • $$3.1 \times 10^{-4} m$$
  • $$6.5 \times 10^{-5} m$$
  • $$6.5 \times 10^{-4} m$$
  • $$9.2 \times 10^{-4} m$$
An object is placed at a distance of 1.5 m from a screen and a convex lens is interposed between them. The magnification produced isThe focal length of the lens is :
  • $$1 m$$
  • $$0.5 m$$
  • $$0.24 m$$
  • $$2 m$$
The near point of a hypermetropic person is 75 cm from the eye. What is the power of the lens required to enable the person to read clearly a book held at 25 cm from the eye?
  • $$1\ D$$
  • $$1.5\ D$$
  • $$0.75\ D$$
  • $$2.67\ D$$
Choose the correct answer from alternatives given.
The mixture of a pure liquid and a solution in a long vertical column (i.e, horizontal dimensions <<vertical dimensions) produces diffusion of solute particles and hence a refractive index gradient along the vertical dimension. A ray of light entering the column at right angles to the vertical is deviated from its original path. Find the deviation in travelling a horizontal distance d << h, the height of the column. 
943891_b32746aed2e7463f931650c66def2463.png
  • $$- \, \dfrac{1}{d} \, \left(\frac{du}{dy} \right)\mu$$
  • $$ \dfrac{d}{h} \, \left(\frac{du}{dy} \right)$$
  • $$\left(\frac{du}{dy} \right)h$$
  • $$- \, \dfrac{1}{\mu} \, \left(\frac{du}{dy} \right)d$$
Ocean appears blue due to _____________________.
  • Greater depth
  • Scattering of light by water particles
  • Blue colour of water
  • None of these
Which defect of vision of eye is shown respectively?
947983_2d684267417a4ce68586a6dbfad6ed8c.png
  • P: Presbyopia, Q: Near sightedness
  • P: Far sightedness, Q: Near sightedness
  • P: Near sightedness, Q: Far sightedness
  • P: Presbyopia, Q: Far sightedness
In the given figure, the radius of curvature of a curved surface for both the piano-convex and plano-concave lens is 10 cm and refractive index for both is 1.The location of the final image after all the refractions through lenses is:
943769_eeee1428430641a8a0df896adf796c5c.png
  • $$15 cm$$
  • $$20 cm$$
  • $$25 cm$$
  • $$40 cm$$

A sphere of radius $$R$$ is placed in air such that its centre is at origin. A ray of light traveling along $$y =  + \dfrac{{\sqrt 3 }}{2}R$$ (in x-y plane) is incident on this sphere.

If ray travels through sphere as shown in figure, then:


970342_5bb039cea74341e2b31fc86e309697c0.png
  • Refractive index of the sphere is 2
  • Refractive index of the sphere $$\sqrt 3 $$
  • Emergent ray travels along the line $$\sqrt 3 x + y = \sqrt 3 R$$
  • Total deviation suffered by the ray is $${45^o}$$
A ray of light travelling in water is incident on its surface open to air. The angle of incidence $$\theta,$$ which is less than the critical angle. Then there will be:
  • only a reflected ray and no refracted ray
  • only a refracted ray and no reflected ray
  • a reflected ray and a refracted ray and the angle between them would be less than $$180^{o}-2\theta$$
  • a reflected ray and a refracted ray and the angle between them would be greater than $$180^{o}-2\theta$$
A ray of light travels from water to glass as shown below. The refractive index of water is $$1.3$$ and the refractive index of glass is $$1.5$$. What is the angle of refraction ?
1210219_d4ef5368eed940678645fa8f508ac5dc.png
  • $$30.7^{o}$$
  • $$35.3^{o}$$
  • $$41.7^{o}$$
  • $$48.6^{o}$$
An equal convex lens of $$\upsilon =1.5 $$  has a focal length of 20 cm in air.  Now that lens kept in the medium of refractive index 3.  An object is kept at distance 30 cm from the lens in the same medium.  Find its image distance from the lens is :
  • 24 cm
  • 12 cm
  • 10 cm
  • None
A point object O is placed at a distance of 20 cm in front of a equiconvex lens $$(^a\mu_g \, = \, 1.5)$$ of  focal length 10 cm. The lens is placed on a liquid of refractive index 2 as shown in the figure. An image will be formed at a distance h from a lens. The value of h is
943877_ffb99064421a410ead1a8911c1a39911.png
  • 5 cm
  • 10 cm
  • 20 cm
  • 40 cm
A gain telescope in an observatory has an objective of focal length $$19\ m$$ and an eye-piece of focal length $$1.0\ cm$$. What is the diameter of the image of moon formed by the objective in normal adjustment? The diameter of moon is $$3.5\times {10}^{6}\ m$$ and the radius of the lunar orbit round the earth is $$3.8\times {10}^{8}\ m.$$
  • $$10\ cm$$
  • $$12.5\ cm$$
  • $$15\ cm$$
  • $$17.5\ cm$$
A ray incident at a point at an angle of incidence of $${60}^{o}$$ enters a glass sphere of $$R.l.n=\sqrt 3$$ and is reflected and refracted at the further surface of the sphere. The angel between the reflected and refracted rays at this surface is
  • $${50}^{o}$$
  • $${60}^{o}$$
  • $${90}^{o}$$
  • $${40}^{o}$$
A point object $$O$$ is placed in front of a glass rod having a spherical end of radius of curvature $$30\ cm$$. The image would be formed at :
1069082_1f7dbfe888a4425a9809ed2f28b8fde6.png
  • $$30\ cm$$ left
  • Infinity
  • $$1\ cm$$ to the right
  • $$18\ cm$$ to the left
A ray of light enters a spherical drop of water of refractive index $$\mu$$ as shown in the figure. The angle $$\phi$$ for which minimum deviation is produced will be given by :
1014859_1e8edf8945994526ab20a43de1b6a514.png
  • $$\cos^{2}\phi = \dfrac {\mu^{2} + 1}{3}$$
  • $$\cos^{2}\phi = \dfrac {\mu^{2} - 1}{3}$$
  • $$\sin^{2}\phi = \dfrac {\mu^{2} + 1}{3}$$
  • $$\sin^{2}\phi = \dfrac {\mu^{2} - 1}{3}$$
A spherical refractive surface of radius $$10$$ cm separates two media of refractive indices $$ \mu = 1$$ and $$ \mu = 3/2$$ respectively. A point object P starts from rest at $$t = 0$$ with an acceleration $$2 \ cm s^{-2}$$. Find the speed of image at $$t =1$$ s.
1063600_beb6d940699b45a192e6a3faa4251a9f.PNG
  • $$ 2 cms^-1 $$
  • $$ 6 cms^-1 $$
  • $$ 3.7 cms^-1 $$
  • none of these
One end of a glass rod of refractive index $$n=1.5$$ is spherical surface of radius of curvature $$R$$. The centre of the spherical surface lies inside the glass. A point object placed in air on the axis of the rod at the point $$P$$ has its real image inside glass at the point Q (see figure). A line joining the points P and Q cuts the surface at O such that $$OP=2OQ$$. The distance PO is
1023634_c043d081fa4f49e7bece0e18fca27b93.png
  • $$8R$$
  • $$7R$$
  • $$2R$$
  • None of these
An achromatic combination is made by combining 2 prisms as shown:-
If $$\omega_1 > \omega_2$$, then 
1079271_ba471e06f619498785ade0a53cb7e6cc.PNG
  • Average deviation would be clockwise
  • Average deviation would be anticlockwise
  • Average deviation would be zero
  • Cannot be predicted on basis of give information
A light ray is incident normally on one of the refracting faces of a prism and just emerges  out grazing the second surface. The relation between angle of the prism and its critical angle is
  • $$A=C$$
  • $$A\neq C$$
  • $$A< C$$
  • $$A>C$$
A double convex lens of focal length $$30cm$$ is made of glass. When it is immersed in a liquid of refractive index $$1.5$$, the focal length is found to be $$120cm$$. The critical angle between glass and the liquid is
  • $$\sin ^{ -1 }{ \left( \cfrac { 1}{ 2 } \right) } \quad $$
  • $$\sin ^{ -1 }{ \left( \cfrac { 1 }{ 1.2} \right) } \quad $$
  • $$\sin ^{ -1 }{ \left( \cfrac { 7 }{ 13 } \right) } \quad $$
  • $$\sin ^{ -1 }{ \left( \cfrac { 7 }{ 8 } \right) } \quad $$
After testing the eyes of a child, the optician has prescribed the following lenses for his spectacles:
left eye : $$+ 2\, D$$ Right eye: $$+ 2.25\, D$$
the child is suffering from the defective vision called:
  • Short-sightedness
  • Long-sightedness
  • Cataract
  • Presbyopia
Rays from an object immersed in water $$( \mu = 1.33 )$$ traverse a spherical air bubble of radius R. If the object is located far away from the bubble, its image as seen by the observer located on the other side of the bubble will be 
1195128_00c1fc0dfb7f4f09b55cf15bb4aeb447.png
  • virtual, erect and diminished
  • real, inverted and magnified
  • virtual, erect and magnified
  • real, inverted and diminished
Two Nicol prisms are first crossed and then one of them is rotated through $$30^{0} $$ .The percentage of incident unpolarized light transmitted is  
  • 37.5
  • 50
  • 12.5
  • 25.0
A diverging meniscus of radii of curvatures $$25\ cm \ and \ 50 \ cm $$ has a refractive index $$1.5$$. Its focal length is :
  • $$-50cm$$
  • $$-100cm$$
  • $$100cm$$
  • $$50cm$$
Monochromatic light is incident on a glass prism of angle $$A$$. If the refractive index of the material of the prism is $$\mu$$, a ray, incident at an angle $$\theta$$, on the face $$AB$$ would get transmitted through the face $$AC$$ of the prism provided.q
1336951_7b4e7526a6904f08a35f977b76afdb4a.png
  • $$\theta > \sin^{-1} \left [\mu \sin \left (A - \sin^{-1} \left (\dfrac {1}{\mu}\right )\right )\right ]$$
  • $$\theta < \sin^{-1} \left [\mu \sin \left (A - \sin^{-1} \left (\dfrac {1}{\mu}\right )\right )\right ]$$
  • $$\theta > \cos^{-1} \left [\mu \sin \left (A + \sin \left (\dfrac {1}{\mu}\right )\right )\right ]$$
  • $$\theta < \cos^{-1} \left [\mu \sin \left (A + \sin \left (\dfrac {1}{\mu}\right )\right )\right ]$$
The angular resolution of a radio telescope is to be $${ 0.100 }^{ 0 }$$ when the incident beam of wavelength $$ 3.00mm$$ is used. What is minimum diameter required for the telescope's receiving dish? 
  • 2.0 m
  • 4.20 m
  • 2.20 m
  • 3.20 m
A ray of light is incident on the surface of separating two transparent medium at an angle $$45^0$$ and is refracted in medium at an angle $$30^0$$. Velocity of light in the medium will be...
  • $$3.8 \times 10^8 \ m/s$$ 
  • $$3.38 \times 10^8 \ m/s$$ 
  • $$2.12 \times 10^8 \ m/s$$ 
  • $$1.5 \times 10^8 \ m/s$$ 
Two identical thin isosceles prism of refracting angle 'A' and refractive index $$ \mu $$ are placed their bases touching each other. Two parallel rays of light are incident on this system as shown The distance of the point where the rays converge from the prism is: 
1234719_7cea2f725717483ea93ae3a5e9be9659.jpeg
  • $$ \dfrac { h }{ \mu A } $$
  • $$ \dfrac { h }{ A } $$
  • $$ \dfrac { h }{ \left( \mu -1 \right) a } $$
  • $$ \dfrac { \mu h }{ \left( \mu -1 \right) a } $$
A ray of light makes normal incidence on the diagonal face of a right angled prism as shown in figure. If $$ \theta = 37^o $$, then the angle of deviation after second step (from AB) is (sin $$ 37^o = 3/5 $$ ) 
1223537_a01d4f627a83461b93e1f9ea441eef6c.png
  • $$ 53^o $$
  • $$ 74^o $$
  • $$ 106^o $$
  • $$ 90^o $$
A convex lens (refractive index $$\mu=1.5$$) has a power P. If it is immersed in a liquid ($$\mu $$=4/3), then its power will become will become/remain 
  • P
  • $$\dfrac { P }{ 2 }$$
  • $$\dfrac { P }{ 4 } $$
  • 4P
0:0:1


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