Ray Optics PYQs Set 10 (PDF)

Set 10 of 16 · Questions 271-300 of 467

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Mere Teacher · Previous Year Questions NEET Physics · Ray Optics · Set 10 (Q271-300)
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271. $In a long glass tube, mixture of two liquids A and B with refractive indices 1.3 and 1.4respectively, forms a convex refractive meniscus towards . If an object placed at 13 cm from the vertex of the meniscus in A forms an image with a magnification of then the radius of curvature of meniscus is:$ (1) $\frac{1}{3} cm$ (2) $\frac{4}{3} cm$ (3) $1 cm$ (4) $\frac{2}{3} cm$ 272. $The eye can be regarded as a single refracting surface. The radius of curvature of this surface is equal to that of cornea . This surface separates two media of refractive indices and . Calculate the distance from the refracting surface at which a parallel beam of light will come to focus.$ (1) $1 cm$ (2) $2 cm$ (3) $4.0 cm$ (4) $3.1 cm$ 273. $An object is placed beyond the centre of curvature C of the given concave mirror. If the distance of the object is d_{1} from C and the distance of the image formed d_{2} is from C, the radius of curvature of this mirror is:$ (1) $\frac{2 d _{1} d _{2}}{d _{1} - d _{2}}$ (2) $\frac{2 d _{1} d _{2}}{d _{1} + d _{2}}$ (3) $\frac{d _{1} d _{2}}{d _{1} + d _{2}}$ (4) $\frac{d _{1} d _{2}}{d _{1} - d _{2}}$ 274. $When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index$ (1) $equal to that of glass$ (2) $less than one$ (3) $greater than that of glass$ (4) $less than that of glass.$ 275. $At the first minimum adjacent to the central maximum ofa single‐slit diffraction pattern, the phase difference between the Huygen’s wavelet from the edge of the slit and the wavelet from the midpoint of the slit is$ (1) $π radian$ (2) $\frac{π}{8} radian$ (3) $\frac{π}{4} radian$ (4) $\frac{π}{2} radian$ 276. $The distance between an object and its real image produced by a converging lens is 0.72 m . The magnification is 2 . What will be the magnification when the object is moved by 0.04 m towards the lens?$ (1) $2$ (2) $4$ (3) $3$ (4) $6$ 277. $The refractive index of the material of a prism is and the angle of the prism is . One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is [NEET 2018]$ (1) $30^{\circ}$ (2) $45^{\circ}$ (3) $60^{\circ}$ (4) $zero$ 278. $Two polaroids P_{1} and P_{2} are placed with their axis perpendicular to each other. Unpolarised light I_{0} is incident on P_{1} . A third polaroid P_{3} is kept in between P_{1} and P_{2} such that its axis makes an angle 4 5^{o} with that of P_{1} . The intensity of transmitted light through P_{2} is$ (1) $\frac{I _{0}}{4}$ (2) $\frac{I _{0}}{8}$ (3) $\frac{I _{0}}{16}$ (4) $\frac{I _{0}}{2} .$ 279. $In the Young’s double slit experiment, the intensity of light at a point on the screen where the path difference λ is K, (λ being the wavelength oflight used). The intensity at a point where the path difference is λ /4 will be$ (1) $K$ (2) $K /4$ (3) $K /2$ (4) $zero$ 280. $the following graphs is the correct one, if D_{m} is the angle of minimum deviation?$ (1) (2) (3) (4) 281. $When monochromatic red light is used instead of blue light in a convex lens, its focal length will :$ (1) $increase$ (2) $decrease$ (3) $remain same$ (4) $does not depend on colour of light$ 282. $If f_{V} and f_{R} are the focal lengths of a convex lens for violet and red light respectively and F_{V} and F_{R} are the focal lengths of a concave lens for violet and red light respectively, then we must have$ (1) $f_{V} > f_{R} and F_{V} > F_{R}$ (2) $f_{V} < f_{R} and F_{V} > F_{R}$ (3) $f_{V} > f_{R} and F_{V} < F_{R}$ (4) $f_{V} < f_{R} and F_{V} < F_{R} .$ 283. $A plano convex lens fits exactly into a plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices μ1 and μ2 and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is :$ (1) $\frac{R}{2 ( μ _{1} - μ _{2} )}$ (2) $\frac{R}{( μ _{1} - μ _{2} )}$ (3) $\frac{2 R}{( μ _{2} - μ _{1} )}$ (4) $\frac{R}{2 ( μ _{1} + μ _{2} )}$ 284. $A vessel of depth 2h is half filled with a liquid of refractive index and the upper half with another liquid of refractive index . The liquids are immiscible. The apparent depth of the inner surface of the bottom of vessel will be :$ (1) $\frac{h}{3 2}$ (2) $\frac{3}{4} h 2$ (3) $\frac{h}{2}$ (4) $\frac{h}{2 ( 2 + 1 )}$ 285. $Abubble in glass slab (μ = 1.5) when viewed from one side appears at 5cm and 2cm from other side, then thickness of slab is$ (1) $3.75 cm$ (2) $3 cm$ (3) $10.5 cm$ (4) $2.5 cm$ 286. $The thickness at the center of a plano convex lens is 3 mm and the diameter is 6 cm . If the speed of light inthe material of the lens is 2 \times 10^{8} ms^{- 1} . The focal length of the lens is$ (1) $0.30 cm$ (2) $15 cm$ (3) $1.5 cm$ (4) $30 cm$ 287. $A thin converging lens of focal length 25 cm forms a sharp image of an object on a screen placed at a distance of 75 cm from the lens. Later the screen is moved closer to the lens by a distance 25 cm . The distance through which the object is to be shifted so that its image on the screen is sharp again is$ (1) $50 cm towards the lens$ (2) $50 cm away from the lens$ (3) $12.5 cm towards the lens$ (4) $12.5 cm away from the lens$ 288. $A light whose electric field vectors arc completely removed by using a good Polaroid, allowed to incident on the surface of the prism at Brewster's angle. Choose the most suitable option for the phenomenon related to the prism.$ (1) $Reflected and refracted rays will be perpendicular to each other$ (2) $Wave will propagate along the surface of prism$ (3) $No refraction, and there will be total reflection of light$ (4) $No reflection and there will be total transmission of light.$ 289. $Given a thin convex lens (refractive index ), kept in a liquid (refractive index ) having radii of curvatures and . Its second surface is silver polished. Where should an object be placed on the optic axis so that a real and inverted image is formed at the same place?$ (1) $\frac{μ _{1} ( R _{1} ) \cdot ( R _{2} )}{μ _{2} ( ( R _{1} ) + ( R _{2} ) ) - μ _{1} ( R _{2} )}$ (2) $\frac{μ _{1} ( R _{1} ) \cdot ( R _{2} )}{μ _{2} ( ( R _{1} ) + ( R _{2} ) ) - μ _{1} ( R _{1} )}$ (3) $\frac{( μ _{2} + μ _{1} ( R _{1} ) )}{( μ _{2} - μ _{1} )}$ (4) $\frac{μ _{1} ( R _{1} ) \cdot R _{2} ∣}{μ _{2} ( 2 ( R _{1} ) + ( R _{2} ) ) - μ _{1} R _{1} \| \cdot \| \cdot R _{2} ∣}$ 290. $Car B overtakes another car A at a relative speed of 40 m s^{- 1} . How fast will the image of car B appear to move in the mirror of focal length 10cm fitted in car A, when the car B is 1.9m away from the car A?$ (1) $4 m s^{- 1}$ (2) $0.2 m s^{- 1}$ (3) $40 m s^{- 1}$ (4) $0.1 m s^{- 1}$ 291. $The intensity at the maximum in a Young’s double slit experiment is I_{0} . Distance between two slits is d = 5 λ, where λ is the wavelength oflight used in the experiment. What will be the intensity in front of one of the slits on the screen placed at a distance D = 10 d ?.$ (1) $\frac{3}{4} I_{0}$ (2) $\frac{I _{0}}{2}$ (3) $I_{0}$ (4) $\frac{I _{0}}{4}$ 292. $The speed oflight in media M_{1} and M_{2} are 1.5 \times 1 0^{8} m / s and 2.0 \times 1 0^{8} m / s respectively. A ray of light enters from medium M_{1} to M_{2} at an incidence angle i . Ifthe ray suffers total internal reflection, the value of i is$ (1) $Equal to$ (2) $Equal to or less than$ (3) $Equal to or greater than$ (4) $Less than$ 293. $A concave-convex lens of refractive index 1.5 and the radii of curvature of its surfaces are 30 cm and 20 cm, respectively. The concave surface is upwards and is filled with a liquid of refractive index 1.3. The focal length of the liquid-glass combination will be$ (1) $\frac{700}{11} cm$ (2) $\frac{600}{11} cm$ (3) $\frac{800}{11} cm$ (4) $\frac{500}{11} cm$ 294. $A converging beam of rays is incident on a diverging lens. Having passed through the lens the rays intersect at a point 15 cm from the lens on the opposite side. If the lens is removed, the point where the rays meet will move 5 cm closer to the lens. The focal length of the lens is$ (1) $5 cm$ (2) $- 10 cm$ (3) $20 cm$ (4) $- 30 cm.$ 295. $A ray of light passes from a denser medium to a rarer medium at an angle of incidence . The reflected and refracted rays make an angle of with each other. The angle of reflection and refraction are respectively r and r’. The critical angle is given by :$ (1) $s i n_{(}^{- 1} co t r_{)}$ (2) $t a n_{(}^{- 1} s in i_{)}$ (3) $sin^{- 1} (tan r^{'})$ (4) $s i n_{(}^{- 1} t an r_{)}$ 296. $Consider a glass slab which is silvered at one side and the other side is transparent. Given the refractive index of the glass slab to be 1.5. If a ray of light is incident at an angle of on the transparent side, the deviation of the ray of light from its initial path, when it comes out of the slab is$ (1) $120^{\circ}$ (2) $90^{\circ}$ (3) $45^{\circ}$ (4) $180^{\circ}$ 297. $For an object placed at a distance 2.4 m from a lens, a sharp focused image is observed on a screen placed at a distance 12 cm from the lens. A glass plate of refractive index 1.5 and thickness 1 cm is introduced between lens and screen such that the glass plate plane faces parallel to the screen. By what distance should the object be shifted so that a sharp focused image is observed again on the screen?$ (1) $0.8m$ (2) $3.2m$ (3) $1.2m$ (4) $5.6m$ 298. $The variation of refractive index of a crown glass thin prism with wavelength of the incident light is shown. Which of the following graphs is the correct one, if is the angle of minimum deviation ?$ (1) (2) (3) (4) 299. $A conversing beam of rays is incident on a diverging lens. Having passed though the lens the rays intersect at a point 15 cm from the lens on the opposite side. If the lens is removed the point where the rays meets will move 5 cm closer to the lens. The focal length of the lens is :$ (1) $- 10 cm$ (2) $20 cm$ (3) $- 30 cm$ (4) $5 cm$ 300. $The graph shows how the magnification m produced by a thin lens varies with image distance v . What is the focal length of the lens used?$ (1) $\frac{b ^{2}}{ac}$ (2) $\frac{b ^{2} c}{a}$ (3) $\frac{a}{c}$ (4) $\frac{b}{c}$