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pptics and, , pptical Instruments, , , , , , , , , , , , , , , , , , , , , , , , , , , 4 thin prism having refracting angle 10° is, ° made of glass of refractive index 1.42. This, , rism is combined with another thin prism, of glass of refractive index 1.7. This, combination produces dispersion without, deviation. The refracting angle of second, prism should be [NEET 2017], (a) 4° (b) 6° (c) 8° (d) 10°, , The ratio of resolving powers of an optical, microscope for two wavelengths, , 4, = 4000 A and 4, = 6000 A is [NEET 2017], (8:27 (b)9:4 (c)3:2 (d) 16: 81, , Abeam of light from a source L is incident, normally on a plane mirror fixed at a, certain distance x from the source. The, beam is reflected back as a spot on a scale, placed just above the source L. When the, mirror is rotated through a small angle 6,, the spot of the light is found to move, , ough a distance y on the scale. The, angle 0 is given by [NEET 2017], WE tone @daol ot, , x x 2y y, , Young's double slit experiment is first, ot ormed in air and then in a medium, fin, M0 air. It is found that 8th bright, fine’ © the medium lies where 5th dark, he _¢S in air. The refractive index of, , "edium is nearly [NEET 2017], , (a) 1.25 (b) 1.59 (c) 1.69 (d) 1.78, , 5. Two polaroids P, and P, are placed with, their axis perpendicular to each other., Unpolarised light /, is incident on P,. A, third polaroid P, is kept in between, P, and P, such that its axis makes an angle, 45° with that of P,. The intensity of, transmitted light through P, is [NEET 2017], , I o a I, (a) 3 (b) 7; (c) 5 (@) 16, , 6. The intensity at the maximum in a Young's, double slit experiment is I. Distance, between two slits isd = 5A, where A is the, wavelength of light used in the, experiment. What will be the intensity, infront of one of the slits on the screen, placed at a distance D = 10d? __[NEET 2016], , I |, @ (0) 5h O2 Oh, , 7. In a diffraction pattern due to a single slit, of width a, the first minimum is observed, at an angle 30° when light of wavelength, 5000 A is incident on the slit. The first, secondary maximum is observed at an, angle of [NEET 2016], , (a) sin'(2) (b) oir'(3), , © sin'( 3) @) oin'( 7}

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252, , 8. A astronomical telescope has objective and, eyepiece of focal lengths 40. 6m 4om, , respectively. To view an object 200 om, away from the objective, the lenses must, pneet 2016), , be separated by a distance, , a) 46. 0.0m bh) BOOeM, , (2) 540om a) a7aom, , 9. Match the corresponding entries of we, Column 1 with Column 2. [W here m is, , , irror., magnification produced by the orrer 20rd!, , Column I Column 2, Convex mirror, , b Concave mirror, , Real image =, Virtual image, , a, , , , a) A+ gandc Be aandd Ce+aandb;D>c, , anc, b) As aandd, B+ band, C>+bandd;Dob, , anc, cjA+candd B4bandd;C+bandc;D>a, , anc, i) As dando B+bandc; C+bandd,D>a, , anc, , 10. The angle of incidence for a ray of light at a, refracting surface of a prism is 45°. The, angle of prism is 60°. If the ray suffers, minimum deviation through the prism, the, angle of minimum deviation and refractive, index of the material of the prism, , respectively, are [NEET 2016], (a) 30° 2 (b) 45°; v2, (c) 30° (d) 45°;, , B ba oe, , 11. Two identical glass (u., = 3/2) equi-convex, , lenses of focal length f each are kept in, contact. The space between the two lenses, is filled with water( p,, = 4/3). The focal, , length of the combination is NET 2016], as mf @t mF, 3 4, , 12. An air bubble in a glass slab with refractive, index 1.5 (near normal incidence) is 5 cm, deep when viewed from one surface and, , NEET Chapterwise Solutions - Physi,, , Ai, , A person can see clearly objects OnLy whe ys, ” 2, , . A linear aperture whose width is 0.02 cm, , NN pf, , 0, , 4s, , gem deep when viewed from the a HV , face. The thickness (in cm) of the signet A, ‘, , INtEy ? ai!, , (a) 8 (b) 10 (c) 12 (d 15 yp, , two coherent light sources of intensity, ration. In the interference pattern the, : Tati, , . The interference pattern is obtained wit Vi, i!, , Tmax Trmin will be 48", Imax * min iNeer of, , avi i ang i, @ 2 02 ptrew wy, , n+ n+ (n+ oy, , they lie between 50 cm and 400 cm from, , his eyes. In order to increase the Maxirn, iy’, distance of distinct vision to infinity yy. g, type and power of the correcting lens the F, , person has to use, will be, (a) convex, + 2.25 diopter, (b) concave, - 0 25 diopter, (c) concave — 0.2 diopter, , (d) convex, + 0 15 diopter, , INEET 2016;, , a AAS, , SS, , is placed immediately in front of alens of 2*, focal length 60 cm. The aperture is e, illuminated normally by a parallel beam of <<, wavelength 5 x 10°° cm. The distance of 5, , the first dark band of the diffraction at, , pattern from the centre of the screen is i, INEET 2016}, , (a) 0.10 cm (bo) 0.25 cm, , (c) 0.20 cm (d) 0.15 cm eri, , Two identical thin plano-convex glass q, lenses (refractive index 1.5) each having, radius of curvature of 20 cm are placed, , with their convex surfaces in contact at the s, centre, The intervening space is filled with ite, oil of refractive index 1.7. The focal length, , of the combination is [CBSE AIPMT 2015] Rn, (a)-20cm (b)- 25cm (c)- 50cm (d) 50cm ’ (, , For a parallel beam of monochromatic light {iy, of wavelength ‘A’ diffraction is produ ', by a single slit whose width ‘a’ is of the, order of the wavelength of the light. If'D''s, the distance of the screen from the slit, the, width of the central maxima will be or hs, 2D, [CBSE AIPM Da he, a, , a bp) OR a woe, ) WS or @ar OF

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pris and Optical Instruments, , , , , , , , , , , , Ina double slit experimen, 8s re 1mm apart and the se, ar away. A monochromg, ength 500 nm is use, , 4 the two slits, , Teen is placed, , me weet of, , < width of each slit for Sbutaie -_, axima of double slit within theane, , maxima of single slit pattern? =, , (CBSE Ay), (b) 0.1mm PMT 2015), , (d) 0.02 mm, , ne refracting angle of a prism is A, and, * “active index of the material of the, , em is cot (A/2). The angle of minimum, veviation is (CBSE AIPMT 2015), a= 3A (b) 180°- 24, io (d) 180°+ 24, , an astronomical telescope in normal, adjustment a straight black line of length L, jg drawn on inside part of objective lens,, eye-piece forms a real image of this, line. The length of this image is I. The, magnification of the telescope is, , [CBSE AIPMT 2015], tet (b) =-1, l, L+1 ed, er Ns, , _Two slits in Youngs experiment have, widths in the ratio 1 : 25. The ratio of, intensity at the maxima and minima in the, interference pattern Jnax is, Imin [CBSE AIPMT 2015], , 9 121 49 4, a= b) — (c) — d) =, “ 4 ®) 49 @ 121 @) 9, Abeam of light consisting of red, green, and blue colours is incident on a right, angled prism. The refractive index of the, material of the prism for the above red,, geen and blue wavelengths are 1.39, 1.44, , and 1.47, respectively. [CBSE AIPMT 2015], A, Blue—+—_], TON ——»—_|, Red—+—__1, 45%, , , , 253, , Tho prism will, , , , (a) separate the blue colour part from the red and, green colours, , (b) separate all the three colours from one another, , (c) not separate the th ‘olours at all, , (d) separate the red colour part from the green, and blue colours, , 23. At the first minimum adjacent to the, central maximum of a 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 [CBSE AIPMT 2015], , (a) ™ radian (b) ™ radian (c) m radian (d) ® radian, 4 2 8, , 24. The Young's modulus of steel is twice that, of brass. Two wires of same length and of, same area of cross-section, one of steel and, another of brass are suspended from the, same roof. It we want the lower ends of the, wires to be at the same level, then the, weight added to the steel and brass wires, must be inthe ratio of [CBSE AIPMT 2015], , (1:2 © (b)2:1 (d)1:1, , 25. Light with an energy flux of 25 x 10*, , Wm falls on a perfectly reflecting surface, at normal incidence. If the surface area is, 15cm2, the average force exerted on the, , (c) 4:1, , surface is [CBSE AIPMT 2014], (a) 1.25x10°N (b) 2.50 x 10° N, (c) 1.20 x 10°N (a) 3.0x10°N, , 26. A beam of light of ) = 600 nm from a, distant source falls on a single slit 1 mm, wide and the resulting diffraction pattern, is observed on a screen 2 m away. The, distance between first dark fringes on, either side of the central bright fringe is, , [CBSE AIPMT 2014], , (a) 1.2cm_ (b) 1.2mm (c) 24cm (d) 2.4mm, , 27. In the Young's double-slit experiment, the, intensity of light at a point on the screen, (where the path difference is 4) is K,(a, being the wavelength of light used). The, intensity at a point where the path, difference is A/4, will be [CBSE AIPMT 2014], , (a)k (b) K/4 ()K/2— (d) zero

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and Optical Instruments, vs, , f light travelling in a transparent, aay m of refractive index pt falls, on a, " jarating the medium from air at, , iH, mw se}, s it oF incidence of 45°, For which of, , ao ae wing value of ft the ray can, wing V \, we al reflection?, [CBSE AIPMT 2010], , b) w= 140, 133 (, , @ue id) p = 1.25, yp = 150 @n, , alens h, , f diameter, , aperture of, ; js covered by a black paper. Focal, of lens and intensity of image now, , 4 tively [CBSE AIPMT 2010], — (b) 3! ang!, fend, 4 2, , f |, (d) — and —, > 2, , the intern, ynderge total i, , aving focal length f and aperture, d forms an image of intensity /., , diameter a in central region of, , aw, efend?, , Aboy is trying to start a fire by focusing, sunlight ona piece of paper using an, equiconvex lens of focal length 10 cm. The, diameter of the sun is 1.39x 10° m and its, mean distance from the earth is, , 13x 10"! m. What is the diameter of the, san's image on the paper ? [CBSE AIPMT 2008], )9.2x 10% m (b) 6.5x 10 m, , (65x 10% m (4) 12.4x 104 m, , D Two thin lenses of focal lengths f, and f, we in contact and coaxial. The power of, , , , , , , , , , the combination is [CBSE AIPMT 2008], ff f, a2 b) 2, t w fe, ite ith, : Mh, , P The frequency of a light wave in a material, =i 10 Hz and wavelength is 5000 A., e refractive index of material will be, , 140 [CBSE AIPMT 2007], (9300 (b) 1.50, (a) 1.33, , A lea, smal] aa is resting on the bottom of a, fom th led with a liquid. A ray of light, * coin travels upto the surface of, , the liquid and moves alon:, it, (aes figure} 2 its surface, - Jomn—| Srrrrveres TTT Perrereree, , , , , , Coin, , How fast is the light travelling in the liquid?, [CBSE AIPMT 2007], , (a) 1.8x 10° m/s (b) 2.4% 10? m/s, , (c) 3.0x 10° m/s (d) 1.2 10‘ m/s, , 45. A convex lens and a concave lens, each, , having same focal length of 25 cm, are put, in contact to form a combination of lenses., The power in diopters of the combination, is [CBSE AIPMT 2006], , (a) 25 (b) 50 (c) infinite (d) zero, , 46. A microscope is focussed on a mark on a, piece of paper and then a slab of glass of, thickness 3 cm and refractive index 1.5 is, placed over the mark. How should the, microscope be moved to get the mark in, , focus again ? [CBSE AIPMT 2006], (a) 1 cm upward (b) 4.5 cm downward, (c) 1 cm downward (d) 2. cm upward, , 47, The angular resolution of a 10 cm diameter, telescope at a wavelength of 5000 A is of, , the order of [CBSE AIPMT 2005], (a) 108 rad (b) 10°? rad, (0) 10-4 rad (d) 1078 rad, , 48. A telescope has an objective lens of 10 cm, diameter and is situated at a distance of, one kilometre from two objects. The, minimum distance between these two, objects, which can be resolved by the, telescope, when the mean wavelength of, light is 5000 A, is of the order of, , [CBSE AIPMT 2004], (a)0.6m = (b)5m (c)S5mm_ (d)5cem, , 49. The refractive index of the material of a, prism is ¥2 and its refracting angle is 30°., , One of the refracting surfaces of the prism, is made a mirror inwards, A beam of