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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. |
An infinitely long rod lies along the axis of a concave mirror of focal length f. The near end of the rod is distance `u gt f` from the mirror. Its image will have lengthA. `(uf)/(u-f)`B. `(uf)/(u+f)`C. `(f^(2))/(u+f)`D. `(f^(2))/(u-f)` |
| Answer» Correct Answer - D | |
| 2. |
An infinitely long rod lies along the axis of a concave mirror of focal length f. The near end of the rod is distance `u gt f` from the mirror. Its image will have lengthA. `f^(2)/(u-f)`B. `(uf)/(u-f)`C. `f^(2)/(u+f)`D. `(uf)/(u+f)` |
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Answer» Correct Answer - A (a) From the relation, `1/v+1/u=1/for1/v-1/u=1/(-f)` `1/v=1/u-1/forv=((uf)/(u-f))` Since,`ugtf`,v is negative or `abs(v)=((uf)/(u-f))gtf` The end which is at infinity will have its image at focus. `therefore` Length of image, `L=abs(v)-f=f^(2)/(u-f)` |
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| 3. |
An infinity long rod lies along the axis of a concave mirrror of focal length f.The near end of a the rod is at a distance `ugtf`from the mirror ,Its image will have a length:A. `(f^(2))/(u-f)`B. `(uf)/(u-f)`C. `(f^(2))/(u+f)`D. `(uf)/(u+f)` |
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Answer» Correct Answer - A `(1)/(v)+(1)/(u)=(1)/(f) rArr "let"v_(1)="distance of near end of image"` `(1)/(V_(1))+(1)/(-u)=(1)/(-f) rArr (1)/(v_(1))=(1)/(u)+(1)/(-f) rArr (1)/(v_(1))=(f-u)/(uf)` `v_(1)=(uf)/(f-u)` `v_(2) = "distance of last end is Image" rArr (1)/(v_(2))+(1)/(oo)=(1)/(-f) rArr v_(2)=-f` `"Length of image"|v_(1)-v_(2)|= (uf)/(f-u)-(-f) rArr |v_(1)-v_(2)|=(uf-uf+f^(2))/(u-f)` `|v_(1)-v_(2)| = (f^(2))/(u-f)` |
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| 4. |
STATEMENT-`1`A real object is kept on pricipal axis of mirror.Size of image measured is equal to size of object.The mirror must be plane mirror. `STATEMENT 2` For a plane mirrror magnification is unity.A. STATEMENT -`1`is true statement `2` is true,Statement -`2`is a correct explanation for statement -`1`B. STATEMENT -`1`is true statement `2` is true,Statement -`2`is a not a correct explanation for statement -`1`C. Statement -`1`is true,Statement -`2`is FalseD. Statement -`1`is False ,Statement -`2`is True |
| Answer» Correct Answer - D | |
| 5. |
In the figure shown,the image of a real object is formed at point I.AB is theprincipal axis of the mirror ,The mirrror must be: A. concave & placed towards right `I`B. concave & placed towards left of `I`C. convex & placed towards right of`I`D. convex & placed towards left`I` |
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Answer» Correct Answer - B Since image is magnified and inverted so mirrro in concave and placed also towards left of I. |
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| 6. |
In the figureshownm the image of a real object is formed at point I. AB is the principal axis of the mirror. The mirror must be A. concave and placed towards right of IB. concave and placed towards left of IC. convex and placed towards right of ID. Convex and placed twowards left of I |
| Answer» Correct Answer - A | |
| 7. |
If `._(i)mu_(j)` represents refractive index when a light ray goes from mefium `i` to medium `j`, then the product `._(2)mu_(1)xx._(3)mu_(2)xx._(4)mu_(3)` is equal toA. `._(3)mu_(1)`B. `._(3) mu_(2)`C. `1/(._(1)mu_(4))`D. `._(4)mu_(2)` |
| Answer» Correct Answer - c | |
| 8. |
Statement-1 : it is impossible to photograph a virtual image. Statement-2 : The rays which appear diverging from a virtual image fall on the camera and a real image is captured.A. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is falseD. If assertion is f alse but reason is true |
| Answer» Correct Answer - d | |
| 9. |
The number of images formed by two plane mirrors inclined at `60^@` of an object placed symmetrically between mirror isA. 6B. 2C. 5D. 4 |
| Answer» Correct Answer - c | |
| 10. |
A man holding a lighted candle in front of a thick glass mirror and viewing it obliquely sees a number of images of the candle. What is the origin of these multiple images ? |
| Answer» The origin of multiple images is the multiple reflection of light between the front and back surfaces of glass. Infact, at the front surface of glass, light id partially reflected and partially refracted. The refracted ligt gets reflected at the back surface and then multiple reflections follow within the thickness of glass. They are responsible for multiple images. | |
| 11. |
It is desired to photograph the image of an object placed at a distance of 3 m from the plane mirror. The camera which is at a distance of 4.5 m from the mirror should be focussed for a distance ofA. 3 mB. 4.5 mC. 6 mD. 7.5 m |
| Answer» Correct Answer - d | |
| 12. |
A person is in a room whose ceiling and two adjacent walls are mirrors. How many images are formedA. 5B. 6C. 7D. 8 |
| Answer» Correct Answer - c | |
| 13. |
A thick plane mirror shows a number of images of the filament of an electric bulb. Of these, the brightest image is theA. FirstB. SecondC. FourthD. Last |
| Answer» Correct Answer - b | |
| 14. |
A man is 180 cm tall and his eyes are 10 cm below the top of his head. In order to see his entire height right from tow to head, he uses a plane mirror kept at a distance of 1 m from him. The minimum height of the plane mirror required isA. 180 cmB. 90 cmC. 85 cmD. 170 cm |
| Answer» Correct Answer - b | |
| 15. |
The focal length of an objective of a telescope is 3 metre and diameter 15 cm . Assuming for a normal eye, the diameter of the pupil is 3 mm for its complete use, the focal length of eye piece must beA. 6 cmB. 6.3 cmC. 20 cmD. 60 cm |
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Answer» Correct Answer - A |
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| 16. |
Refractive index of air is `1.0003.` The correct thickness of air column which will have one more wavelength of yellow light `(6000 Å)` than in the same thickness in vacuum isA. 2mmB. 2 cmC. 2mD. 2 km |
| Answer» Correct Answer - c | |
| 17. |
Refractive index of air is `1.0003.` The correct thickness of air column which will have one more wavelength of yellow light `(6000 Å)` than in the same thickness in vacuum isA. 2 mmB. 2 cmC. 2mD. 2 km |
| Answer» Correct Answer - a | |
| 18. |
How can we see a virtual image when it cannot be obtained on a screen ? |
| Answer» True, a virtual image cannot be taken on screen. But our eye lens forms a real image of (virtual image acting as virtual object) on the retina of our eyes. | |
| 19. |
A real image can be…………but a ………..cannot be……….. . |
| Answer» Taken on a screen , virtual image , taken on screen | |
| 20. |
Image formed in a convex mirror is always ………..whatever be………. . |
| Answer» virtual and erect , the position of object | |
| 21. |
A ray `PQ` incident on face `AB` of a prism `ABC`, as shown in Fig., emerges from the face `AC` such that `AQ = AR`. Draw the ray diagram showing the pasage of the ray through the prism. If the angle of prism is `60^@` and refractive index of the material of the prism is `sqrt(3) ,` determine the values of angle of incidence and angle of deviation. . |
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Answer» As the refracted ray passes such that `AQ = AR`, it must go parallel to the base of the prism suffering minimum deviation. `r = A//2 =(60)/(2) = 30^@` `mu = (sin i)/(sin r) = (sin i)/(sin 30^@)` `:. sin i= mu sin 30^@ = sqrt(3) xx (1)/(2)` `i= 60^@` As `i+ e = A + delta_m` `2 i= 60^@ + delta_m, delta_m = 2 [email protected] = 120^@ - 60^@` `delta_m = 60^@`. |
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| 22. |
One cannot cannot see through fog, becauseA. fog absorbs the lightB. light suffers total reflection at dropletsC. refractive index of fog is infinityD. light is scattered by droplets. |
| Answer» Correct Answer - D | |
| 23. |
The refractive index of the material of prism `sqrt3,` then the angle of minimum deviation of prism isA. `30^(@)`B. `45^(@)`C. `60^(@)`D. `75^(@)` |
| Answer» Correct Answer - c | |
| 24. |
An equilateral prism is made of made of material of refractive index `sqrt(3)`. Angle of minimum deviation through the prism is.A. `60^@`B. `30^@`C. `45^@`D. `90^@` |
| Answer» Correct Answer - A | |
| 25. |
The angle of minimum deviation for prism of angle `pi//3 is pi//6`. The refractive index of the material of the prism is.A. `sqrt(3)`B. `sqrt(2)`C. `3//2`D. `2//3` |
| Answer» Correct Answer - B | |
| 26. |
A glass prism has a refracting angle of `60^@`. The angle of minimum deviation is `40^@`. If velocity of light in vacuum is `3 xx 10^8 m//s`. Calculate the velocity of light in glass. What is the angle of incidence ? |
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Answer» Correct Answer - `1.958 xx 10^(8)ms^(-1), 50^(@)` |
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| 27. |
A ray incident normally on one face of a right-angled isosceles glass prism in air is deviated through `90^(@)`. What can you say about the refractive index of glass ? |
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Answer» Correct Answer - `mu gt sqrt(2)` |
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| 28. |
A ray of light incident at `49^(@)` on the face of an equilaternal prism passes symmetrically. Calculate the refractive index of the material of the prism. |
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Answer» Correct Answer - 1.5094 |
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| 29. |
Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more. Reason : Objective lens of large diameter collectd more light.A. If both Assertion and Reason are true and Reason is the correct explantion of AsssertionB. If both Assertion and Reason are true but Reason is not the correct explanation of AssertionC. If Assertion is ture but Reason is falseD. If both Assertion and Reason are false |
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Answer» Correct Answer - A Resolving power of telescope `=(a)/(1.22)lambda` Where, a is the diameter of objective lens and `lambda` is the wavelength of light used. It is obvious that on increasing a more light is collected by objective lens and so, the image formed is more bright. Thus, resolving power of telescope increases. |
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| 30. |
Diameter of the objective of a telescope is 200cm. What is the resolving power of a telescope? Take wavelength of light =5000Å.A. `6.56xx10^(6)`B. `3.28xx10^(5)`C. `1xx10^(6)`D. `3.28xx10^(6)` |
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Answer» Correct Answer - D Given, wavelength of light `lamda=5000 Å=5000xx10^(-10)=5xx10^(-7)m` Diameter of telescope, D=200cm=2m Resolving power of a telescope,=`(1)/(d theta)=(D)/(1.22lamda)` wher, d `theta`=limit of resolution, `lamda`=wavelength of light used D=diameter of aperture of objective So, Resolving paper=`(2)/(1.22x5xx10^(7))=(2xx10^(7))/(6.1)` =`3.278xx10^(6)=3.28xx10^(6)` |
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| 31. |
The diameter of the objective of the telescope is `0.1` metre and wavelength of light is `6000 Å`. Its resolving power would be approximatelyA. `7.32 xx 10^(-6) rad`B. `1.36 xx 10^(6) rad`C. `7.32 xx 10^(-5) rad`D. `1.36 xx 10^(5) rad` |
| Answer» Correct Answer - d | |
| 32. |
The diameter of the objective of a telescope is a, its magnifying power is m and wavelength of light is `lambda`. The resolving power of the telescope isA. `(1.22 lambda)//a`B. `(1.22a)//lambda`C. `lambda m//(1.22a)`D. `a//(1.22 lambda)` |
| Answer» Correct Answer - d | |
| 33. |
The diameter of objective of a telescope is `1m`. Its resolving limit for the light of wave length `4538 Å`, will beA. `5.54 xx 10^(-7) rad`B. `2.54 xx 10^(-4) rad`C. `6.54 xx 10^(-7) rad`D. None of these |
| Answer» Correct Answer - a | |
| 34. |
The resolving power of a telescope whose lens has a diameter of 1.22 m for a wavelength of `5000 Å` isA. `2 xx 10^(5)`B. `2 xx 10^(6)`C. `2 xx 10^(2)`D. `2 xx 10^(4)` |
| Answer» Correct Answer - b | |
| 35. |
A telescope uses light having wavelength 5000 Å and aperture of the objective is 10 cm, then the resolving limit and magnifying power of the telescope is respectivelyA. `6.1xx10^(-6)` rad and 12B. `5.0 xx10^(-6)` rad and 12C. `6.1xx10^(-6)` rad and `8.3xx10^(-2)`D. `5.0xx10^(-6)` rad and `8.3xx10^(-2)` |
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Answer» Correct Answer - A |
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| 36. |
A thin lens made of glass of refractive index `muu = 1.5` has a focal length equal to 12 cm in air. It is now immersed in water (`mu=4/3`). Its new focal length isA. 48 cmB. 36 cmC. 24 cmD. 12 cm |
| Answer» Correct Answer - a | |
| 37. |
The focal length of a thin lens in vacuum is `f`. If the material of the lens has `mu = 3//2`, its focal length when immersed in water of refractive index `4//3` will be.A. fB. `4 f//3`C. 2 fD. 4 f |
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Answer» Correct Answer - D `(1)/(f_a) = ((mu_g)/(mu_a) - )((1)/(R_1) - (1)/(R_2))` …(i) `(1)/(f_w) = ((mu_g)/(mu_w) - )((1)/(R_1) - (1)/(R_2))` ….(ii) Dividing (i) by (ii), we get `(f_w)/(f_a) = ((mu_g//mu_a - 1))/((mu_g//mu_w - )) = ((3//2 - 1))/((3//2)/(4//2) - 1) = (1//2)/(1//8) = 4` `:. f_w = 4 f_a = 4 f`. |
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| 38. |
The refractive index of water is 4 / 3 and that of glass is 5/3. What will be the critical angle for the ray of light entering water from the glassA. `"sin"^(-1) 4/5`B. `"sin"^(-1) 5/4`C. `"sin"^(-1) 1/2`D. `"sin"^(-1) 2/1` |
| Answer» Correct Answer - a | |
| 39. |
What is critical angle for a material of refractive index `sqrt(2)` ? |
| Answer» From `sin C = (1)/(mu)=(1)/(sqrt(2)), C = 45^@`. | |
| 40. |
A light wave travels from glass to water. The refractive index for glass and water are `3/2 ` and `4/3` respectively. The value of the critical angle will be:A. `sin^(-1) (1//2)`B. `sin^(-1) (sqrt(8)/9)`C. `sin^(-1) (8//9)`D. `sin^(-1) (5//7)` |
| Answer» Correct Answer - c | |
| 41. |
If critical angle for a material to air is `30^(@)`, the refractive index of the material will beA. `1.0`B. 1.5C. `2.0`D. 2.5 |
| Answer» Correct Answer - c | |
| 42. |
Relation between critical angles of water and glass isA. `C_(w) gt C_(g)`B. `C_(w) lt C_(g)`C. `C_(w)=C_(g)`D. `C_(w)=C_(g)=0` |
| Answer» Correct Answer - a | |
| 43. |
The reason for shining of air bubble in water isA. Diffraction of lightB. Dispersion of lightC. Scattering of lightD. Total internal reflection of light |
| Answer» Correct Answer - d | |
| 44. |
The speed of light in air is `3xx10^(8) m//s`. What will be its speed in diamond whose refractive index is 2.4A. `3xx10^(8) m//s`B. `332 m//s`C. `1.25xx10^(8) m//s`D. `7.2xx10^(8) m//s` |
| Answer» Correct Answer - c | |
| 45. |
Assertion : The refractive index of diamond is `sqrt(6)` and that of liquid is `sqrt(3)` . If the light travels from diamond to the liquid, it will totally reflected when the angle of incidence is `30^(@)`. Reason : `mu=1/(sin C)`, where `mu` is the refractive index of diamond with respect to liquid.A. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.B. If both Assertion and Reason are true but Reason is not correct explanation of Assertion.C. If Assertion is true but Reason is false.D. If Assertion is false but Reason is true. |
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Answer» Correct Answer - D (d) For total internal reflection the angle of incidence should be greater than the critical angle. As critical angle is `35^(@)`. Therefore, total internal reflection is not possible. |
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| 46. |
Critical angle of light passing from glass to air is minimum forA. RedB. GreenC. YellowD. Violet |
| Answer» Correct Answer - d | |
| 47. |
What is the relation between refractive index and critical angle for a given pair of optical media ? |
| Answer» Correct Answer - `mu = (1)/(sin C)` | |
| 48. |
The critical angle for diamond (refractive index = 2) isA. About `20^(@)`B. `60^(@)`C. `45^(@)`D. `30^(@)` |
| Answer» Correct Answer - d | |
| 49. |
Assertion `:` Critical angle of light passing from glass to air is minimum for violet colour. Reason `:` The wavelength of blue light is greater than the light of other colour.A. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is falseD. If the assertion and reason both are false |
| Answer» Correct Answer - c | |
| 50. |
Assertion `:` Blue colour of sky appears due to scattering of blue colour. Reason `:` Blue colour has shortest wave length in visible spectrum.A. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is falseD. If the assertion and reason both are false |
| Answer» Correct Answer - a | |