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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The optical density of turpentine is higher than that of water, while its mass density is lower. Fig. shows a layer of turpentine floating over water in a container. For which one of the four rays incident on turpentine in Fig., the path shows is correct ? .A. 1B. 2C. 3D. 4 |
| Answer» Here, light ray goes from (optically ) rarer air to optically terpentine, then t bends towards the normal i.e., `i gt r` whereas when it goes from to optically denser medium terpentine to rarer medium water. Then it bends away the normal i.e., | |
| 2. |
A light ray is incident normally on one of the refracting faces of a prism and just emerges out grazing the second surface. Then, the relation between angle of the prism and its critical angle isA. A = CB. `A != C`C. `A lt C`D. `A gt C` |
| Answer» Correct Answer - A | |
| 3. |
A ray of light passes from vaccum into a medium of refractive index n. If the angle of incidence is twice the angle of refraction, then the angle of incidence isA. `sin^(-1)((n)/(2))`B. `2sin^(-1)((n)/(2))`C. `cos^(-1)((n)/(2))`D. `2cos^(-1)((n)/(2))` |
| Answer» Correct Answer - C | |
| 4. |
A light ray of angles of incidence `40^(@)` emerged from the prism in minimum deviation position. Then what is the angle of incidence on the second surface ?A. `90^(@)`B. `0^(@)`C. `40^(@)`D. `20^(@)` |
| Answer» Correct Answer - C | |
| 5. |
A concave mirror is placed on a horizontal table, with its axis directed vertically upwards. Let O be the pole of the mirror and C its centre of curvature. A point object is placed at C. It has a real image, also located at C. If the mirror is now filled with water, the image will be.A. Real, at CB. Real, located beyond CC. Virtual, beyond CD. Real an located before C |
| Answer» Correct Answer - D | |
| 6. |
In the figure shown , for an angle of incidence `45^(@)`, at the top surface , what is the minimum refractive index needed for the internal reflection at vertical face ? A. `sqrt((3)/(2))`B. `sqrt((2)/(3))`C. `sqrt((5)/(2))`D. None of these |
| Answer» Correct Answer - A | |
| 7. |
Statement-1 : A single lens produces a coloured image of an object illuminated by white light. Statement-2 : The refractive index of material of lens is different for different wavelengths of light.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-2B. Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-3C. Statement-1 is True, Statement-2 is falseD. Statement-1 is False, Statement-2 is True |
| Answer» Correct Answer - A | |
| 8. |
A plane mirror is inclined at angle `(alpha gt theta)` with horizontal surface. A particle is projected from point Pat t = 0 with a velocity V at an angle `alpha` with horizontal. The image of the particle is observed from the frame of the particle projected. Assuming the particle does not collide with the mirror, find (i) The time when image will come momentarily at rest with respect to the particle. (ii) Path of image as seen by the particle. |
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Answer» (i) `t = (v cos alpha (tan theta - tan alpha))/(g)` (ii) Straight line. |
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| 9. |
What will be the speed of point P for `theta = 45^(@)` ? |
| Answer» Correct Answer - `4x omega` | |
| 10. |
A mobile phone lies along the principal axis of a concave mirror as shown in Fig. Show by suitable diagram, the formation of its image. Explain why the magnification is not uniform, and distortion will occur depending on the location of the mobile with respect to the mirror. |
| Answer» The ray diagram for the formation of the image of the phone is shown in Fig. 9.7. The image of the part which is on the plane perpendicular to principal axis will be on the same plane. It will be of the same size, i.e., B′C = BC. You can yourself realise why the image is distorted. | |
| 11. |
Two concave refracting surface of equal radii of curvature and refractive index 1.5 face each other in air as shown in figure. A point is placed midway in between the centre and one of the vertices. What is the separation between the image of O formed by each refracting surface ? |
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Answer» We have for the image formed by the surface on the right side. `mu_(1) = 1, mu_(2) = 1.5, u = - R//2, R_(1) = -R` `(mu_(2))/(v) - (mu_(1))/(u) = (mu_(2)-mu_(1))/(2)` `(1.5)/(v) - (2)/(-R) = (1.50-1.00)/(-R)` `:. v = -(3R)/(5)` The image is at a distance of (R - 3R/5) = 0.4 R from the centre P towards the right side. For the surface on the left side, `mu_(1) = 1, mu_(2) = 1.5, u = 3R//2, R_(2) = R` `(mu_(2))/(v) - (mu_(1))/(u) = (mu_(2) - mu_(1))/(R_(2))` `(1.5)/(v) - (2)/(-3R) = (1.50 - 1.00)/(R)` `(1.5)/(v) = (1)/(2R) + (2)/(3R) = (7)/(6R)` `:. v = (9R)/(7)` Hence, the image is at distance of `((9R)/(7-R) = (2R)/(7))` from the centre O towards the right hand side. The distance between the two images = 0.4R - 2R/7 = 0.114R. |
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| 12. |
There are certain materials developed in laboratories which have a negative refractive index, Fig. A ray incident from air (medium 1) into such a medium (medium 2) shall follow a path given by .A. B. C. D. |
| Answer» The negative refractive index metamaterials are those in which incident ray from air (Medium 1) to them refract of bend differently to that of positive refractive index medium. | |
| 13. |
A rectangular block of glass `ABCD` has a refractive index `1.6`. A pin is placed midway on the face`AB`, Fig. When observed from the face `AD`, the pin shall. .A. appear to be near AB. appear to be near DC. appear to be near at the centre of ADD. not be seen at all |
| Answer» For `mu=1.6` the critical angle `mu=1//sin C,` we have C= `38.7^(@)` , when from AD, as long as angle of inidence on AD of the ray emanating from pin is greater than the critical angle, the light suffers from total internal reflection and cannot be seen through AD. | |
| 14. |
Consider an extended object immersed in water contained in a plane through. When seen from close to the edge of the through, the object looks distorted because.A. the apparent depth of the points close to the edge are nearer the surface of the water compared to the points away from the edgeB. the angle substended byt the image of the object at the eye is smaller than the actual angle substended by the object in airC. some of the points of the object far away from the edge may not be visible because of total internal relfectionD. water in a trough acts as lens and magnifies the object |
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Answer» When immersed object is seen from close to the edge of the trough the object looks distorted becauses the apparent depth of the close are nearer the surface of the water compared to the points away from the edge. The angle substended by the image of the object at the eye is smaller than the actual angle substended by the object in air and some of the points of the object for away from the edge may not be visible becauses of total reflection |
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| 15. |
Figure shows an object O kept at P. A plane mirror parallel to yz plane is moving with velocity `3 hat(i) m//s`. Select the correct alternative A. The velocity of image is `6 hat(i) m//s`B. The velocity of image is `-6 hat(i) m//s`C. The velocity of image w.r.t. mirror is `3 hat(i) m//s`D. The velocity of image w.r.t. object is `-6 hat(i) m//s` |
| Answer» Correct Answer - A::C | |
| 16. |
A point object is situated at a distance of 36 cm from the centre of the sphere of radius 12 cm and refractive index 1.5. Locate the position of the image due to refraction through sphere.A. 24 cm from the surfaceB. 36 cm from the centreC. 24 cm from the centreD. Both (1) & (2) |
| Answer» Correct Answer - D | |
| 17. |
Two objects `O_(1)` and `O_(2)` are placed in front of a lens of focal length f. The objects are placed on the principal axis such that `O_(1)O_(2) = x` and `O_(2)` is closer to the lens. The distance of `O_(2)` from lens is greater than its focal length. If their images formed are `I_(1)` and `I_(2)` such that the distance between them is `I_(1)I_(2) = y`, thenA. If `f gt 0, y` must be greater than xB. If `f lt 0, y` must be less than xC. If `f gt 0, I_(2)` may be farther from lens than `I_(1)`D. If `f lt 0, I_(1)` must be farther from lens than `I_(2)` |
| Answer» Correct Answer - B::C::D | |
| 18. |
A parallel beam of monochromatic light falls on a combination of a convex lens and a concave lens of focal lengths 15 cm and 5 cm respectively. What is the distance between the two lenses to obtain a parallel beam of light from the concave lens ?A. 20cmB. 3 cmC. 10 cmD. 45 cm |
| Answer» Correct Answer - C | |
| 19. |
A lens made of material of Refractive index `mu_(2)` is surrounded by a medium of Refractive Index `mu_(1)`. The focal length f is related asA. `f prop (mu_(2) - mu_(1))`B. `f propmu_ (1)/((mu_(2)-mu_(1)))`C. `f prop (mu_(2) + mu_(1))`D. `f prop (1)/((mu_(2)+mu_(1)))` |
| Answer» Correct Answer - B | |
| 20. |
The figure shows a simple arrangement which works as an astronomical telescope. The arrangement consists of two convex lenses placed coaxially. The lens which faces a distant object is called the objective. It has a large aperture and a large focal length also. The second lens is closed to the observers eyes. It is called the eyepiece. It has a smaller aperture as compared to the objective. Its focal length is also small in comparison to objective. The objective forms a real image of a distant object. This image acts as the object for the eyepiece. The eye-piece may form its image at a large distance `(oo)` or at least distance of distinct vision (D = 25 cm). The magnifying power of the telescope is the ratio `(-beta)/(alpha)`. Maximum angular magnification is produced when the final image is at the least distance of distinct vision. The angular magnification produced by the telescope `m = (-beta)/(alpha)`, let focal length of objective lens is `f_(0)` and that of eye-piece lens `f_(e)`. The angular magnification produced, when image formed by the eye-piece is at large distance away, isA. `(-f_(0))/(f_(e))`B. `-(1+(f_(0))/(f_(e)))`C. `(-f_(e))/(f_(0))`D. `-(1+(f_(e))/(f_(0)))` |
| Answer» Correct Answer - A | |
| 21. |
An object is placed 1m in front of the curved surface of a plano-convex lens whose plane surface is silvered. A real image is formed in front of the lens at a distance of 120cm. Then, the focal length of the lens isA. 100 cmB. 200 cmC. 150 cmD. 300 cm |
| Answer» Correct Answer - B | |
| 22. |
A light ray is travelling from air to glass. True reflected and refracted rays are perpendicular to each other. If the angle of incidence in air is I the refractive index of glass isA. sin iB. cos iC. tan iD. cot i |
| Answer» Correct Answer - C | |
| 23. |
A small object is placed 20 cm in front of a block of glass 10 cm thick and its farther side silvered. The image is formed 22 cm behind the silvered face. Find the refractive index of glass.A. 1.15B. 1.25C. 1.67D. 1.1 |
| Answer» Correct Answer - C | |
| 24. |
The radii of curvatures of a convex lens are 0.04 m and 0.04m. Its refractive index is 1.5. Its focal length isA. 0.04 mB. 0.4 mC. 4mD. 40 m |
| Answer» Correct Answer - A | |
| 25. |
The figure shows a simple arrangement which works as an astronomical telescope. The arrangement consists of two convex lenses placed coaxially. The lens which faces a distant object is called the objective. It has a large aperture and a large focal length also. The second lens is closed to the observers eyes. It is called the eyepiece. It has a smaller aperture as compared to the objective. Its focal length is also small in comparison to objective. The objective forms a real image of a distant object. This image acts as the object for the eyepiece. The eye-piece may form its image at a large distance `(oo)` or at least distance of distinct vision (D = 25 cm). The magnifying power of the telescope is the ratio `(-beta)/(alpha)`. Maximum angular magnification is produced when the final image is at the least distance of distinct vision. The length is telescope is the distance between objective lens and eye-piece lens. When the telescope is adjusted to give maximum angular magnification for a distant object the length L of the telescope isA. `L = f_(0) + f_(e)`B. `L lt f_(0) + f_(e)`C. `L gt f_(0) + f_(e)`D. `L = f_(0) - f_(e)` |
| Answer» Correct Answer - B | |
| 26. |
The figure shows a simple arrangement which works as an astronomical telescope. The arrangement consists of two convex lenses placed coaxially. The lens which faces a distant object is called the objective. It has a large aperture and a large focal length also. The second lens is closed to the observers eyes. It is called the eyepiece. It has a smaller aperture as compared to the objective. Its focal length is also small in comparison to objective. The objective forms a real image of a distant object. This image acts as the object for the eyepiece. The eye-piece may form its image at a large distance `(oo)` or at least distance of distinct vision (D = 25 cm). The magnifying power of the telescope is the ratio `(-beta)/(alpha)`. Maximum angular magnification is produced when the final image is at the least distance of distinct vision. A telescope has an objective of focal length 50 cm and an eye-piece of focal length 5 cm. The least distance of distinct vision is 25 cm. The telescope is adjusted for distinct vision and it is focussed on an object 200 cm away. The length of the telescope isA. `(425)/(6)cm`B. 55 cmC. 53 cmD. 45 cm |
| Answer» Correct Answer - A | |
| 27. |
A converging beam of light is incident on a concave lens. The beam converges behind the lens at 15 cm from its centre, in the absence of the lens. Select the correct alternativeA. After passing through the lens, beam becomes diverging, what ever may be the focal lengthB. If focal length = 10 cm, the beam diverges awayC. If focal length = 20 cm, the beam diverges awayD. Focal length = 30 cm, beam converged at focal point of the lens |
| Answer» Correct Answer - B::D | |
| 28. |
A convex lens of focal length 20 cm is placed in front of a convex mirror of focal length 15 cm at a distance of 5 cm. An object of length 2 cm is placed perpendicular to the common axis at a distance of 20 cm from the lensA. The final image is formed at 163 cm from the lensB. The final image is formed at infinityC. The size of final image is 10.7 cmD. The size of final image is very large |
| Answer» Correct Answer - B::D | |
| 29. |
Three lenses in contact have a combined focal length of 12 cm. When the third lens is removed, the combined focal length is `(60)/(7)` cm. The third lens isA. A converging lens of focal length 30 cmB. A converging lens of foca length 60 cmC. A diverging lens of focal length 30 cmD. A diverging lens of focal length 60 cm |
| Answer» Correct Answer - C | |
| 30. |
If the space between the lenses in the lens combination shown were filled with water, what should happen to the focal length and power of the lens combination ? A. Focal length decreasesB. Power decreasesC. Power increasesD. Focal length increases |
| Answer» Correct Answer - B::D | |
| 31. |
A tank contains a transparent liquid of refractive index `mu`. The bottom of the tank is a plane mirror as shown. A person at P looks at an object O and its image in the mirror. The distance between the object and its image in the mirror as preceived by the person is A. `2 mu d`B. `(2d)/(mu)`C. `(2(H-d))/(mu)`D. `((H+D))/(mu)` |
| Answer» Correct Answer - B | |
| 32. |
A jar of height h is filled wih a transparent liquid of refractive index `mu`, Fig. At the centre of the jar on the botom surface is a dot. Find the minimum diameter of a disc, such that when placed on the top surface symmetrically about the centre, the dot is invisible. . |
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Answer» Let d be the diameter of the disc. The spot shall be invisible if the incident rays from the dot at O to the surface at d/2 at the criticale angle. Let `i` be the angle of inidence Using releatioship between refractive index and critical angle then, `" " sint =(1)/(mu)` ltbr Unsing geometry and trigonometry Now `" " (d//2)/(h)=tani` `rArr " " (d)/(2)=h tan i=h"["sqrt(mu^(2)-1)"]"^(-1)` `:. " " d=(2h)/(sqrt(mu^(2)-1))` This is the required expression of d. |
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| 33. |
In a medium of refractive index 1.6 and having a convex surface has a point object in it at a distance of 12 cm from the pole. The radius of curvature is 6 cm. Locate the image as seen from airA. A real image at 30 cmB. A virtual image at 30 cmC. A real image at 4.28 cmD. A virtual image at 4.28 cm |
| Answer» Correct Answer - B | |
| 34. |
Light travels in two media A and B with speeds `1.8 × 10^(8) m s^(–1) and2.4 × 10^(8) m s^(–1)` respectively. Then the critical angle between them isA. `sin^(-1) ((1)/(5))`B. `sin^(-1) ((4)/(5))`C. `sin^(-1) ((1)/(2))`D. `sin^(-1) ((2)/(3))` |
| Answer» Correct Answer - B | |
| 35. |
A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is.A. blueB. greenC. violentD. red |
| Answer» Since `vproplambda`, the light of red colour is of highest wavelength and therefore of highest speed. Therefore, after travelling through the slab, the red colour emerge first. | |
| 36. |
A passenger in an aeroplane shallA. never see a rainbowB. may see a primary and a secondary rainbow as concentric circlesC. may see a primary and a secondary rainbow as concentric arcsD. shall never see a secondary rainbow |
| Answer» A passenger in an aeroplane may see a primary and a secondary rainbow like concentric circles. | |
| 37. |
An object approaches a convergent lens from the left of the lens with a uniform speed `5 m//s` and stops at the focus. The image.A. moves away from the less with an uniform speed 5/sB. moves away from the less with an uniform accelerationC. moves away from the less with a non-uniform accelerationD. moves towards the lens with a non-uniform acceleration |
| Answer» When an object apporaches a convergent lens from the left of the less with a uniform speed of 5m/s, the image away from the lens with a non-uniform acceleration. | |
| 38. |
An astronomical refractive telescope has an objective of focal length `20 m` and an eyepiece of focal length `2 cm`.A. The length of the telescope tube is 20.2 mB. The magnification is 1000C. The image formed is invertedD. An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image |
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Answer» The length of the telescope tube uis `f_(0)+f_(e)=20+(0.02)=20.2m` Asloc, `" " m=20//0.02=1000` Also, the image formed in inverted. |
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| 39. |
A plane mirror `(M_1)` and a concave mirror `(M_2)` of focal length 10 cm are arranged as shown in figure. An object is kept at origin. Answers the following questions. (consider image formed by single reflection in all cases). The coordination of image formed by plane mirror areA. `-20 cm` , 0 cmB. 10 cm, `-60 cm`C. 10cm, `-10 cm`D. 10 cm, 10 cm |
| Answer» Correct Answer - C | |
| 40. |
A plane mirror `(M_1)` and a concave mirror `(M_2)` of focal length 10 cm are arranged as shown in figure. An object is kept at origin. Answers the following questions. (consider image formed by single reflection in all cases). If concave mirror is replaced by convex mirror of same focal length then coordinates of image formed by `(M_2)` will beA. 10 cm, 12 cmB. 10 cm, 22 cmC. 10 cm, 8 cmD. None of these |
| Answer» Correct Answer - D | |
| 41. |
A plane mirror `(M_1)` and a concave mirror `(M_2)` of focal length 10 cm are arranged as shown in figure. An object is kept at origin. Answers the following questions. (consider image formed by single reflection in all cases). If concave mirror is replaced by convex mirror of same focal length then coordinates of image formed by `(M_2)` will beA. 10cm, -10 cmB. 10 cm, -60 cmC. 10 cm, 8 cmD. None of these |
| Answer» Correct Answer - D | |
| 42. |
Light incident normally on a plane mirror attached to a galvanometer coil retraces backwards a shown in Fig. 6(a). 14. A current in the coil produces a deflection of `3.5^(@)` in the mirror. What is the displacement of the reflected spot of light on a screen placed `1.5 m` away ? |
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Answer» Angle of deflection, `theta=3.5^(@)` Distance of the screen from the mirror, D=1.5m The reflected rays get deflected by an amount twice the angle of deflection i.e. 20= `7.0^(@)`. the displacement d) of the reflected spot of ligh on the screen is given as: `tan2theta=d/1.5` `therefore d=1.5 xx tan7^(@)` = 0.184 m =18.4 cm Hence, the displacement of the reflected spot of light is 18.4 cm. |
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| 43. |
A beam of light is partially reflected and partially refracted from a surface. The angle between reflected and refracted light ray is `90^(@)`. If the angle of refraction is `30^(@)`, the angle of incidence isA. `60^(@)`B. `48^(@)`C. `45^(@)`D. `90^(@)` |
| Answer» Correct Answer - A | |
| 44. |
A glass slab of thickness `4 cm` contains the same number of waves as `5 cm` of water, when both are traversed by the same monochromatic light. If the refractive index of water is `4//3,` then refractive index of glass isA. `(5)/(3)`B. `(5)/(4)`C. `(16)/(15)`D. `(3)/(2)` |
| Answer» Correct Answer - A | |
| 45. |
For an eye kept at a depth h inside water is refractive index `mu`, and viewed outside, the radius of circle through which the outer objects can be seen will beA. `(h)/(sqrt(mu^(2)-1))`B. `(h)/(mu)`C. `(h)/(sqrt(mu^(2)+1))`D. `((sqrt(mu^(2)-1))/(mu))h` |
| Answer» Correct Answer - A | |
| 46. |
While a moving picture is being screened, a boy introduced a glass slab of thickness 3 cm and refractive index 1.5 between the projector and the screen. In order to have a clear picture on the screen the screen should be moved through a distance ofA. 1 cm awayB. 1 cm nearerC. 2 cm awayD. 3 cm away |
| Answer» Correct Answer - A | |
| 47. |
In optical fibre, refractive index of inner part is 1.68 and refractive index of outer part is 1.44. The numerical aperture of the fibre isA. 0.5653B. 0.6553C. 0.7653D. 0.8753 |
| Answer» Correct Answer - D | |
| 48. |
A travelling microscope is focussed on to a scratch on the bottom of a beaker. Water of refractive index `(4)/(3)` is poured in it. Then the microscope is to be lifted through 2 cm focus it again. Find the depth of water in the beaker.A. 4 cmB. 8 cmC. `(8)/(7)cm`D. `(8)/(3) cm` |
| Answer» Correct Answer - B | |
| 49. |
White light is incident on the interface of glass and air as shown in figure. If green ligth is just totally internally reflected then the emerging ray in air contains A. Yellow, orange, redB. Violet, indigo, blueC. All coloursD. All colours except green |
| Answer» Correct Answer - A | |