Ray Optics PYQs Set 9 (PDF)

Set 9 of 16 · Questions 241-270 of 467

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Mere Teacher · Previous Year Questions NEET Physics · Ray Optics · Set 9 (Q241-270)
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241. $A spherical surface separates two media of refractive indices 1 and 1.5 as shown in figure. Distance of the image of an object ' ', is:( C is the center of curvature of the spherical surface and is the radius of curvature)$ (1) $0.24 m left to the spherical surface$ (2) $0.24 m right to the spherical surface$ (3) $0.4 m left to the spherical surface$ (4) $0.4 m right to the spherical surface$ 242. $A vessel of depth d is half filled with oil of refractive index hi and the other half is filled with water of refractive index . The apparent depth of this vessel when viewed from above will be-$ (1) $\frac{2 d ( n _{1} + n _{2} )}{n _{1} + n _{2}}$ (2) $\frac{d ( n _{1} + n _{2} )}{2 n _{1} n _{2}}$ (3) $\frac{d n _{1} n _{2}}{2 ( n _{1} + n _{2} )}$ (4) $\frac{d n _{1} n _{2}}{( n _{1} + n _{2} )}$ 243. $An upright object is placed at a distance of 40 cm in frontof a convergent lens of focal length 20 cm . A convergentmirror of focal length 10 cm is placed at a distance of 60 cm on the other side of the lens. The position and size of thefinal image will be:$ (1) $20 cm from the convergent mirror, same size as theobject$ (2) $40 cm from the convergent mirror, same size as theobject$ (3) $40 cm from the convergent lens, twice the size of the object$ (4) $20 cm from the convergent mirror, twice the size of the object$ 244. $A thin convex lens made from crown glass has focal length f. When it is measured in two different liquids having refractive indices and , it has the focal lengths f1 and f2 respectively. The correct relation between the focal length is :$ (1) $f1 = f2 < f$ (2) $f1 > f and f2 becomes negative$ (3) $f2 > f and f1 becomes negative$ (4) $f1 and f2 both become negative$ 245. $The position of final image formed by the given lens combination from the third lens will be at a distance of (f_{1} = + 10 cm, f_{2} = - 10 cm), and (f_{3} = + 30 cm)$ (1) $15 cm .$ (2) $infinity$ (3) $45 cm$ (4) $30 cm$ 246. $A beam of light both reflects and refracts at the surface between air and glass. The index of refraction of the glass is 1.4. If the refracted and the reflected rays are perpendicular to each other, then the angle of incidence in the air is$ (1) $tan^{- 1} (1.4)$ (2) $sin^{- 1} (\frac{1}{1.4})$ (3) $tan^{- 1} (\frac{1}{1.4})$ (4) $sin^{- 1} (\frac{1.4}{π})$ 247. $A light ray incidents normally on one surface of an equilateral prism. The angle of deviation of the light ray is (refractive index of the material of the prism )$ (1) $60^{\circ}$ (2) $30^{\circ}$ (3) $0^{\circ}$ (4) $120^{\circ}$ 248. $A point like object is placed at a distance of 1 m in front of a convex lens of focal length 0.5 m . A plane mirror is placed at a distance of 2 m behind the lens. The position and nature of the final image formed by the system is$ (1) $2.6 m from the mirror, real$ (2) $1 m from the mirror, real$ (3) $2.6 m from the mirror, virtual$ (4) $1 m from the mirror, virtual$ 249. $For a plano convex lens has radius ofcurvature 10 cm. It is silvered on its plane surface. Find focal length after silvering.$ (1) $10 cm$ (2) $20 cm$ (3) $15 cm$ (4) $25 cm.$ 250. $Find the value of the angle of emergence from the prism. Refractive index of the glass is . [NEET 2021]$ (1) $60^{\circ}$ (2) $30^{\circ}$ (3) $45^{\circ}$ (4) $90^{\circ}$ 251. $A point source of light is kept below the surface of water (n_{w} = \frac{4}{3}) at a depth of 7 m . The radius of the circular bright patch of light noticed on the surface of water is ... m .$ (1) $\frac{3}{7}$ (2) $3$ (3) $\frac{7}{3}$ (4) $7$ 252. $The refractive index of water is 1.33. What will be the speed oflight in water?.$ (1) $4 \times 1 0^{8} m / s$ (2) $1.33 \times 1 0^{8} m / s$ (3) $3 \times 1 0^{8} m / s$ (4) $2.25 \times 1 0^{8} m / s .$ 253. $Three rays of light, namely red , green and blue arc incident on the face of a right angled prism as shown in figure.The refractive indices of the material of the prism for red, green and blue wavelength are and respectively. The colour of the ray(s) emerging out of the face is:$ (1) $green$ (2) $red$ (3) $blue and green$ (4) $blue$ 254. $If a ray of light in denser medium strikes a rarer medium at an angle of incidence , the angles of reflection and refraction are and respectively. If the reflected and refractive rays are at right angles to each other, the critical angle for the given pair of media is$ (1) $sin^{- 1} (tan r^{’})$ (2) $sin^{- 1} (tan r)$ (3) $tan^{- 1} (sin i)$ (4) $cos^{- 1} (tan i)$ 255. $A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is$ (1) $10 cm$ (2) $15 cm$ (3) $2.5 cm$ (4) $5 cm.$ 256. $In the figure shown here, what is the equivalent focal length of the combination of lenses (Assume that all layers are thin)? [NEET 2023]$ (1) $-40 cm$ (2) $-100 cm$ (3) $-50 cm$ (4) $40 cm$ 257. $An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is$ (1) $16$ (2) $8$ (3) $10$ (4) $12$ 258. $A concave lens and a convex lens are arranged as shown in the figure. The position of the final image.$ (1) $17 cm to the left of convex lens$ (2) $24.2 cm to the right of concave lens$ (3) $29.2 cm to the right of concave lens$ (4) $24.2 cm to the left of convex lens$ 259. $The speed of light in media 'A' and 'B' are 2.0 x 1 0^{10} cm/s and 1.5 x 1 0^{10} chm/s respectively. A ray of light enters from the medium B to A at an incident angle ' θ'. If the ray suffers total internal reflection, then$ (1) $θ = sin^{- 1} (\frac{3}{4})$ (2) $θ > sin^{- 1} (\frac{2}{3})$ (3) $θ < sin^{- 1} (\frac{3}{4})$ (4) $θ > sin^{- 1} (\frac{3}{4})$ 260. $A ray of light is incident normally on one face of a right angled isosceles prism. It then grazes the hypotenuse. The refractive index of the material of the prism is$ (1) $1.33$ (2) $1.414$ (3) $1.5$ (4) $1.732$ 261. $Light enters from air into a given medium at an angle of with interface of the air-medium surface. After refraction, the light ray is deviated through an angle of from its original direction. The refractive index of the medium is$ (1) $1.732$ (2) $1.333$ (3) $1.414$ (4) $2.732$ 262. $Three lenses of focal lengths + 10 cm, - 10 cm and + 30 cm are placed at distance of 30 cm, 35 cm and 45 cm, respectively from an object. The distance between the object and the image formed is$ (1) $100 cm$ (2) $75 cm$ (3) $30 cm$ (4) $45 cm$ 263. $A plano-convex lens having radius of curvature of first surface 2 cm exhibits focal length ofin air. Another plano-convex lens with first surface radius of curvature 3 cm has focal length of when it is immersed in a liquid of refractive index 1.2. If both the lenses are made of same glass of refractive index 1.5, the ratio of and will be$ (1) $1 : 2$ (2) $1 : 3$ (3) $3 : 5$ (4) $2 : 3$ 264. $An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is [NEET 2016]$ (1) $8$ (2) $10$ (3) $12$ (4) $16$ 265. $A beam oflight from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L . When the mirror is rotated through a small angle Θ, the spot of the light is found to move through a distance y on the scale. The angle 6 is given by$ (1) $\frac{y}{x}$ (2) $\frac{x}{2 y}$ (3) $\frac{x}{y}$ (4) $\frac{y}{2 x}$ 266. $Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the center. The intervening space is filled with oil of refractive index 1.7. The focal length of the combination is$ (1) $-20 cm$ (2) $-25 cm$ (3) $-50 cm$ (4) $50 cm$ 267. $A transparent film of refractive index, 2.0 is coated on a glass slab of refractive index, 1.45.What is the minimum thickness of transparent film to be coated for the maximum transmission of Green light of wavelength 550 nm. [Assume that the light is incident nearly perpendicular to the glass surface.]$ (1) $137.5 nm$ (2) $275 nm$ (3) $94.8 nm$ (4) $68.7 nm$ 268. $A convex lens with lateral magnification 2 is used to image a point at the bottom of a tank. The image of the point is formed above the lens. Now a liquid is filled into the tank to a height of . It is found that the distance of the image of the same point is now 120 above the lens. Find the refractive index of the liquid.$ (1) $1.31$ (2) $1.33$ (3) $1.36$ (4) $1.39$ 269. $A convex mirror of radius of curvature 30 cm forms an image that is half the size of the object. The object distance is :$ (1) $- 15 cm$ (2) $45 cm$ (3) $- 45 cm$ (4) $15 cm$ 270. $An empty tank has concave mirror as its bottom. When sunlight falls normally on the mirror, it is focused at a height of from the mirror. If the tank is filled with water upto a height of , then the sunlight focusses at (refractive index of water )$ (1) $16 cm above water level$ (2) $9 cm above water level$ (3) $16 cm below water level$ (4) $9 cm below water level.$