InterviewSolution
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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.
| 501. |
An intially parallel cyclindrical beam travels in a medium of refractive index `mu (I) = mu_(0) + mu_(2) I`, where `mu_(0)` and `mu_(2)` are positive constants and `I` is intensity of light beam. The intensity of the beam is decreasing with increasing radius. Answer the following questions : As the beam enters the medium, it willA. convergeB. diverge near the axis and converge near the peripheryC. travel as a cyclindrical beamD. diverge |
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Answer» Correct Answer - A As the medium is denser w.r.t. vacuum, therefore, on entering the medium, it will converge. |
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| 502. |
Power `(P)` of a lens is given by reciprocal of focal length `(f)` of the lens. i.e. `P = 1//f`. When `f` is in metre, `P` is in dioptre. For a convex lens, power is positive and for a concave lens, power is negative. When a number of thin lenses of powers `p_(1), p_(2), p_(3)....` are held in contact with one another, the power of the combination is given by algebraic sum of the powers of all the lenses i.e., `P = p_(1) + p_(2) + p_(3) + ........` Answer the following questions : Power of second lens isA. `-3.75 D`B. `0.5 D`C. `-5 D`D. `1.25 D` |
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Answer» Correct Answer - A `P_(2) = P - P_(1) = (100)/(F) - (100)/(f_(1))` `:. P_(2) = (100)/(80) - (100)/(20) = 12.5 - 5 = - 3.75 D` |
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| 503. |
The final image in a astronomical telescope (w.r.t. object) is.A. virtual and erectB. real and erectC. real and invertedD. virtual and inverted |
| Answer» Correct Answer - D | |
| 504. |
what is the relation between `f and R` of a spherical mirror ? |
| Answer» Correct Answer - `f = R//2` | |
| 505. |
How is speed of light in vacuum affected by change in wavelength//intensity of light ? |
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Answer» Speed of light in vaccume is an absolute constant. It is not affected by change in wavelength/intensity of light. |
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| 506. |
When does a concave mirror form a virtual image ? |
| Answer» When the object is placed between the pole and principal focus of the mirror. | |
| 507. |
A small object is kept symmetrically between two plane mirrors inclined at 38°. This angle is now gradually increased to 41°, the object being symmetrical all the time. Determine the number of images visible during the process. |
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Answer» The object is kept symmetrically between two plane mirrors. This implies the object is placed at angle bisector. Thus, for θ = 38°, n = \(\frac{360}{38}\) = 9.47 As it is not integral, N = 9 (the integral part of n) ∴ For going from 38° to 41°, the mirrors go through angles 39° and 40°. Number of images formed will remain 9 for all angles between 38° and 40°. For angles > 40°, the n goes on decreasing and when θ = 41°, n = \(\frac{360}{41}\) = 8.78 i.e., N = 8 |
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| 508. |
At which positions of the objects do spherical mirrors produce (i) diminished image (ii) magnified image? |
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Answer» i. Amongst the two types of spherical mirrors, convex mirror always produces a diminished image at all positions of the object. ii. Concave mirror produces diminished image when object is placed :
iii. Concave mirror produces magnified image when object is placed :
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| 509. |
In case of image formation by plane mirrors -A. Object can be real and image virtualB. Both object and image can be virtualC. Both object and image can be realD. None of these |
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Answer» Correct Answer - A |
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| 510. |
A plane mirror rotating at an angular velocity of 3 radian/s reflects a light beam. The angular velocity of the reflected beam is -A. `3 "rad"//s`B. `6 "rad"//s`C. `9 "rad"//s`D. `12 "rad"//s` |
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Answer» Correct Answer - B |
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| 511. |
Angular dispersion of a prism is……….of………..and……….colours. |
| Answer» the difference in the angles of deviation , violet , red. | |
| 512. |
How does the speed of light in glass change (a) on increasing the wavelength of light ? (b) on increasing the intensity of light ? |
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Answer» (i) Speed of light in glass increases on increasing the wavelength (ii) There is no effect of changing intensity on speed of light in glass. |
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| 513. |
What is Tyndall Scattering? |
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Answer» The scattering of light rays by the colloidal particles in the colloidal solution is called Tyndall Scattering or Tyndall Effect. |
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| 514. |
What is meant by colloid ? state few examples. |
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Answer» Colloid is a microscopically small substance that is equally dispersed throughout another material. Eg: Milk, Ice cream, muddy water, smoke. |
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| 515. |
Rays of light are falling on a convex lens of focal length `40 cm`. As shown in Fig. Determine the position of the image. . |
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Answer» Correct Answer - `8 cm` `f = + 40 cm, u = + 10 cm, v = ?` `(1)/(v) = (1)/(f) + (1)/(u) = (1)/(40) + (1)/(10) = (5)/(40) = (1)/(8)` `v = 8 cm` |
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| 516. |
In the minimum deviation position, the………. In the prism is……… to the base of the prism. |
| Answer» refracted ray , parallel | |
| 517. |
What is meant by Raman Scattering? |
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Answer» When a parallel beam of monochromatic (single coloured) light passes through a gas or liquid or transparent solid, a part of light rays are scattered. |
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| 518. |
Define Raman Scattering |
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Answer» Raman scattering is defined as " The interaction of light ray with the particles of pure liquids or transparent solids, which leads to change in wavelength or frequency." |
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| 519. |
Wavelength of violet colour is……… wavelength of red colour. Therefore, `mu_v` …………`mu_r`. Hence, `delta_v` ………. `delta_r`. |
| Answer» less than , is greater than , is greater than. | |
| 520. |
A ray of light undergoes………on passing through a prism. |
| Answer» Correct Answer - two refractions | |
| 521. |
When does a ray passing through a prism deviate away from the base of the prism ? |
| Answer» This happens when prism is immersed in a medium of refractive index higher than the refractive index of material of the prism. | |
| 522. |
A thin prism of `6^@` angle gives a deviation of `3^@`. The refractive index of the material of the prism is.A. `1`B. `4//3`C. `3//2`D. `2` |
| Answer» Correct Answer - C | |
| 523. |
When size of scatterer (x) is very much less than the wavelength `(lamda)` of light, intensity of scattered light `(I_s)` varies as :A. `I_(s) prop (1)/(lambda)`B. `I_(s) prop (1)/(lambda^(2))`C. `I_(s) prop (1)/(lambda^(4))`D. `I_(s) prop (1)/(lambda^(6))` |
| Answer» Correct Answer - C | |
| 524. |
On what factors does the dispersive power of a prism depend ? |
| Answer» Nature of material of the prism. | |
| 525. |
What are the factors on which angular dispersion of a prism depend ? |
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Answer» (i) Angle of prism (ii) nature of material of the prism. |
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| 526. |
What is angle of deviation through a prism ? |
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Answer» it is the angle between the incident ray on the prism, and emergent ray from the prism. |
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| 527. |
A glass prism is immersed completely in water. How does angle of minimum deviation change ? |
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Answer» Angle of minimum deviation decreases because `.^(w)mu_(g) lt .^(a)mu_(g)`, and `mu = (sin (A + delta_(m))//2)/(sin A//2)` |
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| 528. |
On what factors does of deviation produced by a prism depend ? |
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Answer» Deviation produced by a prism depends on (i) angle of incidence (ii) angle of prism (iii) nature of material of prism (iv) colour/wavelength of light. |
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| 529. |
For which colour, red and blue, is the refractive index of glass greater ? |
| Answer» Refractive index of glass is greater for blue colour than that for red colour. | |
| 530. |
What is the relation between angle of prism `A`, angle of incidence `i` and angle of minimum deviation `delta_(m)` ? |
| Answer» `delta_(m) = 2 i - A`. | |
| 531. |
A convex lens has focal length of 2.0 cm. Find its magnifying power if image is formed at DDV. |
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Answer» Given: f = 2 cm, v = D = 25 cm To find: Magnifying power (M.P.) Formula: M.P = 1 + \(\frac{D}{f}\) Calculation: From formula, M.P = 1 + \(\frac{25}{2}\) M.P. = 1 + 12.5 = 13.5 |
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| 532. |
What is the relation between angle of prism `A`, angle of incidence `i` and angle of minimum deviation `delta_(m)` ?A. `i = A + delta_(m)`B. `i = (A + delta_(m))/(2)`C. `delta_(m) = i + A`D. `delta_(m) = i - A` |
| Answer» Correct Answer - B | |
| 533. |
The deviation `delta` of a ray on passing through a prism of small angle `A` is. |
| Answer» given by the relation `delta = (mu - 1) A` | |
| 534. |
The deviation `delta` of a ray on passing through a prism of small angle `A` is.A. `(mu - 1)/(A)`B. `(A)/(mu - 1)`C. `(mu - 1)A`D. None of these |
| Answer» Correct Answer - C | |
| 535. |
In glass, the velocity of light is minimum forA. redB. violetC. yellowD. green |
| Answer» Correct Answer - B | |
| 536. |
In vaccum, which colour travels fastest ?A. redB. violetC. greenD. none of the above |
| Answer» Correct Answer - D | |
| 537. |
What is yellow spot ? |
| Answer» It is a spot at about the centre of the retina, which is most sensitive to light. | |
| 538. |
What is range of vision ? |
| Answer» Range of vision is the distance between near point and far point of eye. | |
| 539. |
What is Rayleigh line ? |
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Answer» The spectral lines having frequency equal to the incident ray frequency is called 'Rayleigh line'. |
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| 540. |
What is meant by accommodation of the eye ? |
| Answer» it is the ability of the eye to observe distinctly the objects situated at widely different distqances fron the eye. | |
| 541. |
What is Rayleigh scattering ? |
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Answer» The scattering of sunlight by the atoms or molecules of the gases in the earth's atmosphere is known as Rayleigh scattering. |
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| 542. |
What is the power of accommodation of the eye? |
Answer»
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| 543. |
Why the colour of the sun is red at sunrise and sunset? |
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Answer» At sunrise and sunset, the light rays from the Sun have to travel a larger distance in the atmosphere than at noon. Hence, most of the blue lights are scattered away and only the red light which gets least scattered reaches us. Therefore, the colour of the Sun is red at sunrise and sunset. |
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| 544. |
What are the causes of ‘Myopia’? |
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Answer» 1. The lengthening of eye ball. 2. The focal length of eye lens is reduced. 3. The distance between eye lens and retina increases. 4. The far point will not be at infinity. 5. The far point comes closer. |
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| 545. |
Why are traffic signals red in colour? |
Answer»
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| 546. |
Why does the sky appear blue in colour? |
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Answer» When sunlight passes through the atmosphere, the blue colour (shorter wavelength) is scattered to a greater extent than the red colour (longer wavelength). This scattering causes the sky to appear blue in colour. |
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| 547. |
Find the radius of curvature of convex surface of a plano convex lens, whose focal length is `0.3 m and mu = 1.5`. |
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Answer» Here, `R_(1) = oo, R_(2) = ?`, `f = 0.3 m, mu = 1.5` From `(1)/(f) = (mu - 1)((1)/(R_(1)) - (1)/(R_(2)))` , `(1)/(0.3) = (1.5 - 1)((1)/(oo) - (1)/(R_(2)))` `-(1)/(R_(2)) = (1)/(0.3 xx 0.5) = (100)/(15)` , `R_(2) = -(15)/(100) = -0.15 m` |
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| 548. |
A double convex lens made of glass of refractive index `1.56` has both radii of curvature of magnitude `20 cm`. If an object is placed at a distance of `10 cm` from this lens, find the position of image formed. |
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Answer» Here, `mu = 1.56, R_(1) = 20 cm`, `R_(2) = -20 cm, u = -10 cm, v = ?` As `(1)/(f) = (mu -1)((1)/(R_(1)) - (1)/(R_(2)))` :. `(1)/(f) = (1.56 - 1)((1)/(20) + (1)/(20)) = 0.56 xx (1)/(10)` `f = (10)/(0.56) = 17.86cm`. As `(1)/(v) - (1)/(u) = (1)/(f) :. (1)/(v) = (1)/(f) + (1)/(u) = (1)/(17.86) + (1)/(-10)` `v = -22.72 cm` |
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| 549. |
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. `-(1)/(15)m//s`B. `10 m//s`C. `15 m//s`D. `(1)/(10) m//s` |
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Answer» Correct Answer - A From mirror formula (using convex mirror) `(1)/(u) + (1)/(v) = (1)/(f)` …(i) Using `u = - 2.8 m = -280 cm, f = 20 cm` `:. (1)/(- 280) + (1)/(v) = (1)/(20) or (1)/(v) = (1)/(20) + (1)/(280) = (15)/(280)` or `v = (280)/(15)cm` Differentiating (i) w.r.t `t`, we have `-(1)/(u^(2))(d u)/(dt) - (1)/(v^(2))(dv)/(dt) = 0` or `(d v)/(dt) = -(v^(2))/(u^(2))((d u)/(dt))` `:.` Relative velocity of image, `v_(1) = (d v)/(dt) = -(v^(2))/(u^(2))((d u)/(dt)) = (- (280 //15^(2)))/((-280)^(2)) xx 15` `= -(1)/(15)m//s` |
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| 550. |
Select the WRONG statement.(A) Smaller angle of prism is recommended for greater angular dispersion. (B) Right angled isosceles glass prism is commonly used for total internal reflection. (C) Angle of deviation is practically constant for thin prisms. (D) For emergent ray to be possible from the second refracting surface, certain minimum angle of incidence is necessary from the first surface. |
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Answer» Correct answer is (A) Smaller angle of prism is recommended for greater angular dispersion. |
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