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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.
| 201. |
When light wave suffers reflection at the interface from air to glass, the change in phase of the reflected wave is equal toA. zeroB. `pi/2`C. `pi`D. `2pi` |
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Answer» Correct Answer - C (c ) From a rarer to denser medium, a phase difference of `pi` occurs. |
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| 202. |
The ratio of resolving powers of an optical microscope for two wavelengths `lambda_1=4000Å` and `lambda_2=6000Å` isA. `8 : 27`B. `9 : 4`C. `3 : 2`D. `16 : 81` |
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Answer» Correct Answer - C As resolving power of an optical microscope varies inversely as wavelength of light used, therefore `(RP_1)/(RP_2) = (lamda_2)/(lamda_1) = (6000)/(4000) = 3 : 2`. |
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| 203. |
When a ray of light is incident normally on one refracting surface of an equilateral prism (Refractive index of the material of the prism `=1.5`A. Emerging ray is deviated by `30^(@)`B. Emerging ray is deviated by `45^(@)`C. Emerging ray just grazes the second refracting surfaceD. The ray undergoes total internal reflection at the second refracting surface |
| Answer» Correct Answer - d | |
| 204. |
Statement-1 : When a prism of `mu = 3//2` is immersed in water `(mu = 4//3)`, deviation through the prism becomes `1//4th` of the deviation, when the prism is in air. Statement-2 : It follows from `delta = (mu - 1)A`A. Statement - 1 true, Statement - 2 is true. Statement - 2 is correct explanation of statement - 1.B. Statement - 1 is true, Statement - 2 is true, but Statement - 2 is not a correct explanation of Statement - 1.C. Statement - 1 is true, Statement - 2 is false.D. Statement - 1 is false, Statement - 2 is true. |
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Answer» Correct Answer - A When prism is in air, `delta_a = (mu -1) A = (3//2 - 1) A = A//2` When prism is in water, `delta_m = ((mu_g)/(mu_w) - ) A = ((3//2)/(4//3) - 1) A = (A)/(8) = (delta_a)/(4)` Both the statement are true and statement-2 is correct explanation of statement-1. |
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| 205. |
Statement-1 : Light travels faster in glass than in air. Statement-2 : Because air is rarer than glass.A. Statement - 1 true, Statement - 2 is true. Statement - 2 is correct explanation of statement - 1.B. Statement - 1 is true, Statement - 2 is true, but Statement - 2 is not a correct explanation of Statement - 1.C. Statement - 1 is true, Statement - 2 is false.D. Statement - 1 is false, Statement - 2 is true. |
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Answer» Correct Answer - D Light travels faster in air than in glass, because glass is denser than air. Statement-1 is flase, but statement-2 is true. |
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| 206. |
The concave surface of a thin concavo-convex lens of index`1.5`has radius of curvature `50cm` and`10cm` respectively.The concave side is silvered andplaced on a horizontal surface as shown `Focal length of silvered lens is:A. `30cm`B. `25cm`C. `15cm`D. `10cm` |
| Answer» Correct Answer - B | |
| 207. |
The figure ,shows a transparent sphere of radius`R`and refractive index`mu`.An object `O`is placed at a distance `x` from the pole of the first surface so that a real image is formed at the pole of the exactly opposite surface. If `x=oo`,then the value of `mu` isA. `1.5`B. `2`C. `3`D. None of these |
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Answer» Correct Answer - B `(mu_(2))/(v)-(mu_(1))/(u)=(mu_(2)-mu_(1))/(R ) rArr (u)/(2R)-(1)/(oo)=(mu-1)/(R ) rArr (mu)/(2)=mu-1` `(mu)/(2)=1 rArr mu=2` |
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| 208. |
The figure ,shows a transparent sphere of radius`R`and refractive index`mu`.An object `O`is placed at a distance `x` from the pole of the first surface so that a real image is formed at the pole of the exactly opposite surface. If `x=2R`,then the value of `mu`isA. `1.5`B. `2`C. `3`D. none of these |
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Answer» Correct Answer - C `(mu_(2))/(v)-(mu_(1))/(u)=(mu_(2)-mu_(1))/(R ) rArr(mu)/(2R)-(1)/(-2R)=(mu-1)/(2R)` `(mu)/(2R)=(mu-1)/(R )-(1)/(2R) rArr (mu)/(2R)=(2mu-2-1)/(2R)` `mu=2 mu-3` ` mu=3` |
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| 209. |
Resolving power of a microscope depends uponA. The focal length and aperture of the eye lensB. The focal lengths of the objective and the eye lensC. The apertures of the objective and the eye lensD. The wavelength of light illuminating the object |
| Answer» Correct Answer - d | |
| 210. |
When the object is self-luminous, the resolving power of a microscope is given by the expressionA. `(2mu sin theta)/(1.22 lambda)`B. `(mu sin theta)/(lambda)`C. `(2mu cos theta)/(1.22 lambda)`D. `(2mu)/(lambda)` |
| Answer» Correct Answer - a | |
| 211. |
Finger prints are observed by the use ofA. TelescopeB. MicroscopeC. Gallilean telescopeD. Concave lens |
| Answer» Correct Answer - b | |
| 212. |
The refractive index of the material of the prism for violet colour is 1.69 and that for red is 1.65. If the refractive index for mean colour is 1.66, the dispersive power of the material of the prismA. 0.66B. 0.06C. 0.65D. 0.69 |
| Answer» Correct Answer - b | |
| 213. |
The power of two convex lenses A and B are 8 diopters and 4 diopters respectively. If they are to be used as a simple microscope, the magnification ofA. B will be greater than AB. A will be greater than BC. The information is incompleteD. None of the above |
| Answer» Correct Answer - b | |
| 214. |
The refractive indices for the light of violet and red colours of any material are 1.66 and 1.64 respectively. If the angle of prism made of this material is `10^(@)`, then angular dispersion will beA. `0.20^(@)`B. `0.10^(@)`C. `0.40^(@)`D. `1^(@)` |
| Answer» Correct Answer - a | |
| 215. |
If the refractive angles of two prisms made of crown glass are `10^(@)` and `20^(@)` respectively, then the ratio of their colour deviation powers will beA. `1 : 1`B. `2 : 1`C. `4 : 1`D. `1 : 2` |
| Answer» Correct Answer - d | |
| 216. |
Assertion `:` An empty test tube dipped into water in a beaker appears silver, when viewed from a suitable direction. Reason `:` Due to refraction of light, the substance in water appears silvery.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 | |
| 217. |
What is the wavelength region of visible spectrum ? |
| Answer» `3800 Å` to `7600 Å`. | |
| 218. |
The angle of prism is `5^(@)` and its refractive indices for red and violet colours are 1.5 and 1.6 respectively. The angular dispersion produced by the prism isA. `7.75^(@)`B. `5^(@)`C. `0.5^(@)`D. `0.17^(@)` |
| Answer» Correct Answer - c | |
| 219. |
Assertion `:` Dispersion of light occurs because velocity of light in a material depends upon its colour. Reason `:` The dispersive power depends only upon the material of the prism, not upon the refracting angle of the prismA. 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 - b | |
| 220. |
Assertion `:` The images formed by total internal reflections are much brighter than those formed by mirrorrs or lenses. Reason `:` There is no loss of intensity in total internal reflection.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 |
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Answer» Correct Answer - A `100%` of incident light is reflected back into the same medium ,and there is no loss of intensity,while in reflection from mirrors and refraction from lense =s,there is always some loss of intensity ,Therefore ,images formed by total internal refleciton aremuch brighter than those formed by mirrors of lenses. |
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| 221. |
Assertion `:` The focal length of the lens does not change when red light is replaced by blue light. Reason`:` The focal length of lens does not depends on colour of light used.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 - d | |
| 222. |
Assertion `:` The focal length of the lens does not change when red light is replaced by blue light. Reason`:` The focal length of lens does not depends on colour of light used.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 |
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Answer» Correct Answer - D The focal length of a Lens Is given be formula`(1)/(f)=(mu-1)((1)/(R_(1))-(1)/(R_(2)))` as `mu_(b) gt mu_(R) therefore f_(b) lt f_(r)` therefore focal length o flens decreases when red light is replaced by blue light. |
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| 223. |
A car is fitted with a convex side-view mirror of focal length 20 cm. A second car 2.8m behind the first car is overtaking the first car at a relative speed of 15 `m/s`. The speed of the image of the second car as seen in the mrror of the first one is:A. `10m//s`B. `15m//s`C. `1//10m//s`D. `1//15m//s` |
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Answer» Correct Answer - 2 `(1)/(v)+(1)/(u)=(1)/(f)` `-(1)/(v^(2))(dv)/(dt)-(1)/(u^(2))(du)/(dt)=0 rArr (dv)/(dt)=-(v^(2))/(u^(2))((du)/(dt))` `f=20cm` `(1)/(u)+(1)/(-280)=(1)/(20) rArr v=(280)/(15)cm` `v_(1)=-((280)/(15xx280))^(2)xx15 =(1)/(15)m//s` |
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| 224. |
A thin prism of angle `15^(@)` made of glass of refractive index `mu_(1)=1.5` is combined with another prism of glass of refractive index `mu_(2)=1.75`. The combination of the prism produces dispersion without deviation. The angle of the second prism should beA. `7^@`B. `10^@`C. `12^@`D. `5^@` |
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Answer» Correct Answer - B Here, `A_1 = 15^ @, mu_1 = 1.5 , mu_2 = 1.75, A_2 = ?` There will be no deviation for the combination of two prisms of net deviation is zero, i.e., `delta_1 + delta_2 = 0` or `(mu_1 - 1) A_1 + (mu_2 - 1) A_2 = 0` or `A_2 = -((mu_1 - 1)A_1)/((mu_2 - 1)) = -((1.5 - 1)15^@)/((1.75 - 1)) = - 10^@` `-ve` sign shows that the second prism is placed in opposition to first prism. |
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| 225. |
A thin prism P with angle `4^(@)` and made from glass of refractive index 1.54 is combined with another thin prism P made from glass of refractive index 1.72 to produce dispersion without deviation The angle of prism P isA. `5.33^(@)`B. `4^(@)`C. `2.6^(@)`D. `3^(@)` |
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Answer» Correct Answer - D (d) For a thin prism angle of minimum deviation is given by `delta=(mu-1)A` where, `mu` is refractive index of the prism and A is the angle of prism For dispersion without deviation, `delta_(1)=delta_(2)rArr(mu_(1)-1)A_(1)=(mu_(2)-1)A_(2)` `rArr A_(2)=((mu_(1)-1))/((mu_(2)-1))A_(1)` Given, `mu_(1)=1.54,A_(1)=4^(@),mu_(2)=1.72` `rArrA_(2)=((1.54-1))/((1.72-1))xx4=3^(@)` |
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| 226. |
Light takes 8 min 20 sec to reach from sun on the earth. If the whole atmosphere is filled with water, the light will take the time `(._(a)mu_(w)=4//3)`A. 8 min 20 secB. 8 minC. 6 min 11 secD. 11 min 6 sec |
| Answer» Correct Answer - d | |
| 227. |
There is an equiconcave glass lens with radius of each face as R and `._(a)mu_(g) = 3//2` and `._(a)mu_(W) = 4//3` . If there is water in object space and air in image space, then the focal length isA. 2 RB. RC. `3 R//2`D. `R^(2)` |
| Answer» Correct Answer - c | |
| 228. |
Consider the situation shown in figure. Water `(mu_(w) = (4)/(3))` is filled in a breaker upto a height of 10 cm. A plane mirror is fixed at a height of 5 cm from the surface of water. Distance of image from the mirror after reflection from it if an object O at the bottom of the beaker is A. 15 cmB. `12.5 cm`C. `7.5 cm`D. 10 cm |
| Answer» Correct Answer - B | |
| 229. |
In Fig. a plane mirror lies at a height h above the bottom of a beaker containingwater (refractive index `mu`) upto a height f. Find the position of the image of the |
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Answer» Correct Answer - Image is formed behind the mirror at a distance `=h -t +(t)/(mu)` |
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| 230. |
A plane mirror is placed at the bottom of the tank containing a liquid of refractive index `mu`. P is a small object at a height h above the mirror. An observer O vertically above P, outside the liquid sees P and its image in the mirror. The apparent distance between these two will beA. `2 mu h`B. `(2h)/(mu)`C. `(2h)/(mu-1)`D. `h(1+(1)/(mu))` |
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Answer» Correct Answer - B |
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| 231. |
Sir C.V. Raman was awarded Nobel Prize for his work connected with which of the following phenomenon of radiationA. ScatteringB. DiffractionC. InterferenceD. Polarisation |
| Answer» Correct Answer - a | |
| 232. |
An under water swimmer is at a depth of 12 m below the surface of water. A bird is at a height of 18 m from the surface of water, directly above his eyes. For the swimmer the bird appears to be at a distance from the surface of water equal to (Refractive Index of water is 4/3)A. 24 mB. 12 mC. 18 mD. 9 m |
| Answer» Correct Answer - a | |
| 233. |
The sky would appear red instead of blue ifA. Atmospheric particles scatter blue light more than red lightB. Atmospheric particles scatter all colours equallyC. Atmospheric particles scatter red light more than the blue lightD. The sun was much hotter |
| Answer» Correct Answer - c | |
| 234. |
the reason of seeing the sun a little before the sunrise isA. Reflection of the lightB. Refraction of the lightC. Scattering of the lightD. Dispersion of the light |
| Answer» Correct Answer - b | |
| 235. |
Wavelength of light used in an optical instrument are `lambda_(1) = 4000 Å` and `lambda_(2) = 5000Å` then ratio of their respective resolving powers (corresponding to `lambda_(1)` and `lambda_(2)`) isA. `16 :25`B. `9:1`C. `4:5`D. `5:4` |
| Answer» Correct Answer - d | |
| 236. |
Three immiscible liquids of densities `d_1 gt d_2 gt d_3` and refractive indices `mu_1 gt mu_2 gt mu_3` are put in a beaker. The height of each liquid column is `(h)/(3)`. A dot is made at the bottom of the beaker. For near normal vision, find the apparent depth of the dot.A. `h/6(1/(mu_(1))+1/(mu_(2))+1/(mu_(3)))`B. `h/6(1/(mu_(1))-1/(mu_(2))-1/(mu_(3)))`C. `h/3(1/(mu_(1))-1/(mu_(2))-1/(mu_(3)))`D. `h/3(1/(mu_(1))+1/(mu_(2))+1/(mu_(3)))` |
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Answer» Correct Answer - D Apparent depth of the dot `= (h)/(3mu_(1)) + (h)/(3mu_(2)) + (h)/(3mu_(3)) = (h)/(3)[(1)/(mu_(1))+(1)/(mu_(2)) + (1)/(mu_(3))]` |
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| 237. |
If the central portion of a convex lens is wrapped in black paper as shown in figure A. No image will be formed by the remaining portion of the lensB. The full image will be formed but it will be less brightC. The central portion of the image will be missingD. There will be two images each produced by one of the exposed portions of the lens |
| Answer» Correct Answer - b | |
| 238. |
A convex lens of focal length 10 cm is painted black at the middle portion as shown in figure. An object placed at a distance of 20 cm from the lens. Then A. only one image will be formed by the lensB. the distance between the two images formed by such a lens is 6 mmC. the distance between the images is 4 mmD. the distance between the images is 2mm |
| Answer» Correct Answer - A | |
| 239. |
A ray of light passes through an equilateral glass prism in such a manner that the angle of incidence is equal to the angle of emergence and each of these angles is equal to 3/4 of the angle of the prism. The angle of deviation isA. `45^(@)`B. `39^(@)`C. `20^(@)`D. `30^(@)` |
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Answer» Correct Answer - D (d) Given, `i=e=3/4A=3/4xx60^(@)=45^(@)` In the position of minimum deviation, `2i=A+delta_(m)` or `delta_(m)=2i-A` `2xx45^(@)-60=30^(@)` |
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| 240. |
A ray of light undergoes deviation of `30^(@)` when incident on an equilateral prism of refractive index `sqrt(2)`. The angle made by the ray inside the prism with the base of the prism isA. `15^(@)`B. `0^(@)`C. `45^(@)`D. `30^(@)` |
| Answer» Correct Answer - B | |
| 241. |
A ray of light is incident normally on one of the faces of a prism of apex angle 30 degree and refractive index sqrt2. The angle of deviation of the ray is…degrees.A. `26^(@)`B. `0^(@)`C. `23^(@)`D. `15^(@)` |
| Answer» Correct Answer - d | |
| 242. |
When light rays are incident on a prism at an angle of `45^(@)`, the minimum deviation is obtained. If refractive index of the material of prism is `sqrt(2)`, then the angle of prism will beA. `30^(@)`B. `75^(@)`C. `90^(@)`D. `60^(@)` |
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Answer» Correct Answer - B (d) refractive index of prism, `µ=(sin""(A+delta_(m))/2)/(sin""A/2)rArri=45^(@)=(A+delta_(m))/2` So, `sin45^(@)/sin(A//2)=sqrt2` So, `1/2=sin""A/2rArrA=60^(@)` |
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| 243. |
The minimum deviations suffered by red, yellow and violet beams passing passing through an equilateral transparent prism are `38.4^@, [email protected] and 39.2^@` respectively. Calculate the dispersive power of the medium. |
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Answer» Correct Answer - `0.018` As the prism is equilaterial, `:. A = (180)/(3) = 60^@` `(delta_m)_r = 38.4^@, (delta_m)_y = 38.7^@, (delta_m)_v = 39.2^@` `:.mu_r = ("sin" (A + delta_m)/(2))/(sin A//2) = ("sin"(60^@ + 38.4^@)/(2))/(sin 30^@)` `= (sin 49.2^@)/(1//2) = 1.514` `mu_y = ("sin"(60^@ + 38.7^@)/(2))/(sin 30^@) = (sin 49.35^@)/(1//2) = 1.5184` `mu_v = ("sin"(60^@ + 39.2^@)/(2))/(sin 30^@) = (sin 49.6^@)/(1//2) = 1.523` `omega = (mu_v - mu_r)/(mu_y - 1) = (1.523 - 1.514)/(1.5184 - 1) = (0.009)/(0.5184) = 0.018`. |
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| 244. |
White light is passed through a prism of angle `4^(@)`. If the refractive indices for red and blue colours are 1.641 are 1.659 respectively, then calculate the angle of deviation between them, also calculate the dispersive power. |
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Answer» Angle of deviation, `delta=(mu_(y)-1)A=((mu_(r)+mu_(b))/2-1)4^(@)` =`((1.641+1.659)/2-1)xx4^(@)=(1.65-1)xx4^(@)=2.6^(@)` Dispersive power, `omega=(mu_(b)-mu_(r))/(mu_(y)-1)=(1.659-1.641)/(1.650-1)=0.028` |
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| 245. |
Angle of a prism is `30^(@)` and its refractive index is `sqrt(2)` and one of the surface is silvered At what angle of incidence a ray should be incident on one surface so that after reflection from the silvered surface it retraces its pathA. `30^(@)`B. `60^(@)`C. `45^(@)`D. `sin^(-1)sqrt(1.5)` |
| Answer» Correct Answer - c | |
| 246. |
If the refractive indices of a prism for red, yellow and violet colours be `1.61, 1.63` and `1.65` respectively, then the dispersive power of the prism will beA. `(1.65-1.62)/(1.61-1)`B. `(1.62-1.61)/(1.65-1)`C. `(1.65-1.61)/(1.63-1)`D. `(1.65-1.63)/(161-1)` |
| Answer» Correct Answer - c | |
| 247. |
Formula for dispersive power is (where symbols have their usual meanings) or if the refractive indices of crown glass for red, yellow and violet colours are respectively `mu_(r),mu_(y)` and `mu_(v)` then the dispersive power of this glass would beA. `(mu_(v)-mu_(y))/(mu_(r)-1)`B. `(mu_(v)-mu_(r))/(mu_(y)-1)`C. `(mu_(v)-mu_(y))/(mu_(y)-mu_(r))`D. `(mu_(v)-mu_(r))/(mu_(y))-1` |
| Answer» Correct Answer - b | |
| 248. |
Band spectrum is produced byA. HB. HeC. H2D. Na |
| Answer» Correct Answer - c | |
| 249. |
The refractive indices of a prism for red, violet and yellow lights are `1.52, 1.62` and `1.59` resp. What is the dispersive power of the prism ? If mean deviation is `40^@`. What is angular dispersion produced by the prism ? |
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Answer» Correct Answer - `0.169 ; 6.76^@` Here, `mu_r = 1.52, mu_v = 162 and mu_y = 1.59` Dispersive power (omega) =`(mu_v - mu_r)/(mu_y -1) = (1.62 - 1.52)/(1.59 - 1) = (0.10)/(0.59) = 0.169` Angular dispersion : `delta_v - delta_r = omega xx delta` =`0.169 xx 40^@ = 6.76^@`. |
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| 250. |
For a material the refractive indices for red violet and yellow colour light are respectively 1.52, 1.64 and 1.60 The dispersive power of the material isA. 2B. 0.45C. 0.2D. 0.045 |
| Answer» Correct Answer - c | |