Ray Optics PYQs Set 13 (PDF)

Set 13 of 16 · Questions 361-390 of 467

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Mere Teacher · Previous Year Questions NEET Physics · Ray Optics · Set 13 (Q361-390)
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361. $A beam of light propagating at an angle α_{1} from a medium 1 through to another medium 2 at an angle α_{2} . If the wavelength of light in medium 1 is λ_{1}, then the wavelength of light in menium 2, (λ_{2}), is$ (1) $\frac{s i n α _{2}}{s i n α _{1}} λ_{1}$ (2) $\frac{sin α _{1}}{sin α _{2}} λ_{2}$ (3) $\frac{α _{1}}{α _{2}} λ_{1}$ (4) $λ_{1}$ 362. $Given below are two statements: Statement (I) : When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side. Statement (II) : Concave lens always forms a virtual and erect image. In the light of the above statements, choose the correct answer from the options given below :$ (1) $Both Statement I and Statement II are true$ (2) $Both Statement I and Statement II are false$ (3) $Statement I is true but Statement II is false$ (4) $Statement I is false but Statement II is true$ 363. $At the interface between two materials having refractive indices and , the critical angle for reflection of an em wave is . The material is replaced by another material having refractive index such that the critical angle at the interface between and materials is . If ; and , then is$ (1) $sin^{- 1} (\frac{1}{6})$ (2) $sin^{- 1} (\frac{1}{3})$ (3) $sin^{- 1} (\frac{- 5}{6})$ (4) $sin^{- 1} (\frac{2}{3})$ 364. $In finding out refractive index of glass slab the following observations were made through travelling microscope 50 vernier scale division divisions on main scale in each cmFor mark on paperFor mark on paper seen through slabFor powder particle on the top surface of the glass slab(MSR Main Scale Reading, Vernier Coincidence)Refractive index of the glass slab is:$ (1) $1.52$ (2) $1.35$ (3) $1.42$ (4) $1.24$ 365. $Rainbow is formed due to$ (1) $scattering and refraction$ (2) $internal reflection and dispersion$ (3) $reflection only$ (4) $diffraction and dispersion.$ 366. $Consider following statements for refraction of light through prism, when angle of deviation is minimum.(A) The refracted ray inside prism becomes parallel to the base.(B) Larger angle prisms provide smaller angle of minimum deviation.(C) Angle of incidence and angle of emergence becomes equal.(D) There are always two sets of angle of incidence for which deviation will be same except at minimum deviation setting.(E) Angle of refraction becomes double of prism angle.Choose the correct answer from the options given below:$ (1) $A, B and E Only$ (2) $B, C and D Only$ (3) $B, D and E Only$ (4) $A, C and D Only$ 367. $Interference is possible in$ (1) $light waves only$ (2) $sound waves only$ (3) $both light and sound waves$ (4) $neither light nor sound waves.$ 368. $Blue colour of sea water is due to$ (1) $image of sky in water$ (2) $refraction of sunlight$ (3) $interference of sunlight reflected from the water surface$ (4) $scattering of sunlight by the water molecules$ 369. $Blue colour of the sky is due to$ (1) $reflection of light$ (2) $refraction of light$ (3) $diffraction of light$ (4) $scattering of light$ 370. $Myopia is due to$ (1) $Elongation of eye ball$ (2) $Irregular change in focal length$ (3) $Shortening of eye ball$ (4) $Older age$ 371. $An object is placed at the focus of concave lens having focal length f. What is the magnification and distance of the image from the optical centre of the lens?$ (1) $210 a$ (2) $Very high, \infty$ (3) $\frac{1}{2}, \frac{f}{2}$ (4) $\frac{1}{4}, \frac{f}{4}$ 372. $Monochromatic light is incident on a glass prism of angle A. If the refractive index of the material of the prism is μ, a ray, incident at an angle θ, on the face AB would get transmitted through the face AC of the prism provided:$ (1) $θ > sin^{- 1} [μ sin (A - sin^{- 1} \frac{1}{μ})]$ (2) $θ < sin^{- 1} [μ sin (A - sin^{- 1} \frac{1}{μ})]$ (3) $θ > cos-1$ (4) $θ < cos-1$ 373. $Match the corresponding entries of Column 1 with Column 2. [Where m is the magnification produced by the mirror] Column 1 (A) m = - 2 (B) m = - \frac{1}{2} (C) m = + 2 (D) m = + \frac{1}{2} Column 2 (p) Convex mirror (q) Concave mirror (r) Real image (s) Virtual image$ (1) $A \to p and s; B \to q and r; C \to q and s; D \to q and r$ (2) $A \to r and s; B \to q and s; C \to q and r; D \to p and s$ (3) $A \to q and r; B \to q and r; C \to q and s; D \to p and s$ (4) $A \to p and r; B \to p and s; C \to p and q; D \to r and s$ 374. $A planoconvex lens has a maximum thickness of 6 cm . When placed on a horizontal table with the curved surface in contact with the table surface, the apparent depth of the bottommost point of the lens is found to be 4 cm . If the lens is inverted such that the plane face of the lens is in contact with the surface of the table, the apparent depth of the center of the plane face is found to be (\frac{17}{4}) cm . The radius of curvature of the lens is$ (1) $68 cm$ (2) $128 cm$ (3) $75 cm$ (4) $34 cm$ 375. $Astigmatism (for a human eye) can be removed by using$ (1) $Concave lens$ (2) $Convex lens$ (3) $Cylindrical lens$ (4) $Prismatic lens$ 376. $A beam ofmonochromatic light is refracted from vacuum into a medium of refractive index 1.5. The wavelength of refracted light will be$ (1) $depend on intensity of refracted light$ (2) $same$ (3) $smaller$ (4) $larger.$ 377. $For a point object, which of the following always produces virtual image in air?$ (1) $Concave mirror$ (2) $Plano-convex lens$ (3) $Convex mirror$ (4) $Biconvex lens$ 378. $The expected graphical representation of the variation of angle of deviation ' δ' with angle of incidence 'i' in a prism is :$ (1) (2) (3) (4) 379. $If yellow light emitted by sodium lamp in Young’s double slit experiment is replaced by monochromatic blue light of the same intensity$ (1) $fringe width will decrease$ (2) $fringe width will increase$ (3) $fringe width will remain unchanged$ (4) $fringes will becomes less intense$ 380. $A thin convex lens (refractive index ) is placed ona plane mirror. When a pin is placed at, such that its real inverted image is formed at itself, as shown in figure. When a liquid of refractive index is put between the lens and the mirror, the pin has to be moved to , such that to get its inverted real image at itself. The value of will be:$ (1) $\frac{4}{3}$ (2) $\frac{3}{2}$ (3) $3$ (4) $2$ 381. $Identify the physical quantity that cannot be measured using spherometer :$ (1) $Radius of curvature of concave surface$ (2) $Specific rotation of liquids$ (3) $Thickness of thin plates$ (4) $Radius of curvature of convex surface$ 382. $and are the parallel sided transparent media of refractive index and respectively. They are arranged as shown in the figure. ray is incident at an angle on the surface of separation of and which is as shown in the figure. After the refraction into the medium , the ray grazes the surface of separation of the media and . Then,$ (1) $\frac{n _{3}}{n _{1}}$ (2) $\frac{n _{1}}{n _{3}}$ (3) $\frac{n _{2}}{n _{3}}$ (4) $\frac{n _{1}}{n _{2}}$ 383. $The critical angle for diamond with respect to air is nearly$ (1) $48.8^{\circ}$ (2) $41.1^{\circ}$ (3) $37.3^{\circ}$ (4) $24.4^{\circ}$ 384. $A defective eye cannot see close objects clearly because their image is formed$ (1) $On the eye lens$ (2) $Between eye lens and retina$ (3) $On the retina$ (4) $Beyond retina$ 385. $In young’s double slit experiment, the fringes width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index without disturbing thegeometrical arrangement, the new fringe width will be$ (1) $0.30 mm$ (2) $0.40 mm$ (3) $0.53 mm$ (4) $450 microns.$ 386. $Which of the following statement is incorrect?$ (1) $Dispersion is maximum for violet colour.$ (2) $Red light travels faster than violet light in a medium.$ (3) $In vacuum red light travel faster than others.$ (4) $Refractive index of violet light is higher in flint glass as compared to crown grass.$ 387. $Pick the wrong answer in the context with rainbow.$ (1) $Rainbow is combined effect of dispersion, refraction and reflection of sunlight.$ (2) $When the light rays undergo two internal reflections in a water drop, a secondary rainbow is formed.$ (3) $The order of colours is reversed in the secondary rainbow.$ (4) $An observer can see a rainbow when his front is towards the sun.$ 388. $A convex lens (of focal length 20 cm) and a concave mirror, having their principal axes along the same lines, are kept 80 cm apart from each other. The concave mirror is to the right of the convex lens. When an object is kept at a distance of 30 cm to the left of the convex lens, its image remains at the same position even if the concave mirror is removed. The maximum distance of the object for which this concave mirror, by itself would produce a virtual image would be:$ (1) $30 cm$ (2) $25 cm$ (3) $10 cm$ (4) $20 cm$ 389. $A far sighted man who has lost his spectacles, reads a book by looking through a small hole (3-4 mm) in a sheet of paper. The reason will be$ (1) $Because the hole produces an image of the letters at a longer distance$ (2) $Because in doing so, the focal length of the eye lens is effectively increased$ (3) $Because in doing so, the focal length of the eye lens is effectively decreased$ (4) $None of these$ 390. $A convex lens of focal length 40 cm forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length 20 cm . The photoelectric current now is :$ (1) $\frac{I}{2}$ (2) $4 I$ (3) $2 I$ (4) $I$