Ray Optics Book Back Questions & Answers
Unit 6 > Physics > Class 12 > Samacheer Kalvi - English Medium
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1. The speed of light in an isotropic medium depends on,
(a) its intensity
(b)its wavelength
(c) the nature of propagation
(d) the motion of the source w.r.t medium
Correct answer: (b)its wavelength
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2. 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, (AIPMT Main 2012)
(a) 2.5 cm
(b) 5cm
(c) 10 cm
(d) 15cm
Correct answer: (b) 5cm
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3. An object is placed in front of a convex mirror of focal length of f and the maximum and minimum distance of an object from the mirror such that the image formed is real and magnified. (JEE Main 2009)]
(a) 2f and c
(b) c and
(c) f and O
(d) None of these
Correct answer: (d) None of these
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4. For light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is,
(a) 30o
(b) 45o
(c) 60o
(d) 90o
Correct answer: (a) 30o
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5. Stars twinkle due to,
(a) reflection
(b) total internal reflection
(c) refraction
(d) polarisation
Correct answer: (c) refraction
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6. 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,
(a) less than one
(b) less than that of glass
(c) greater than that of glass
(d) equal to that of glass
Correct answer: (d) equal to that of glass
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7. The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be,
(a) 5 cm
(b) 10 cm
(c) 15 cm
(d) 20 cm
Correct answer: (b) 10 cm
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8. An air bubble in glass slab of 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 of the slab is,
(a) 8 cm
(b) 10 cm
(c) 12 cm
(d) 16 cm
Correct answer: (c) 12 cm
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9. A ray of light travelling in a transparent medium of refractive index n falls, on a surface separating the medium from air at an angle of incidents of 45o . The ray can undergo total internal reflection for the following n,
(a) n = 1.25
(b) n = 1.33
(c) n = 1.4
(d) n = 1.5
Correct answer: (d) n = 1.5