Ans : (c)
285. A man with a dark skin, in comparison with a man with a white skin, will experience [NDA 2010]
           (a) less heat and less cold
           (b) less heat and more cold
           (c) more heat and less cold
           (d) more heat and more cold
Ans : (a)
286. Which one among the following denotes the smallest temperature? [NDA 2010]
           (a) 1° on the Celsius scale
           (b) 1° on the Kelvin scale
           (c) 1° on the Fahrenheit scale
           (d) 1° on the Reaumur scale
Ans : (b)
287. A body initially at rest is acted upon by a constant force. The rate of change of its kinetic energy varies: [NDA 2011]
           (a) linearly with square root of time
           (b) linearly with time
           (c) linearly with square of time
           (d) inversely with time
Ans : (b)
288. Which one among the following statements is correct? [NDA 2011]
           (a) Convex mirrors are used by doctors to examine oral cavity
           (b) Concave mirrors are used as reflectors
           (c) Convex mirrors are used as reflectors
           (d) Convex mirrors should be used for shaving
Ans : (b)
289. A man is at rest in the middle of a horizontal plane of perfectly smooth surface of ice. He can move himself to the shore by making
     use of Newton"s: [NDA2011]
           (a) First law of motion
           (b) Second law of motion
           (c) Third law of motion
           (d) First, second and third laws of motion
Ans : (c)
290. Which one among the following is the major cause of blurring and unsharp images of objects observed through very large telescope
     at the extreme limit of magnification? [NDA 2011]
           (a) Air turbulence of earth"s atmosphere
           (b) Poor optical polish achievable on large mirrors
           (c) Poor tracking capacities of telescopes
           (d) Varying density of air in the Earth"s atmosphere
Ans : (a)
291. Light travels slower in glass than in air because: [NDA 2011]
           (a) refractive index of air is less than that of glass
           (b) refractive index of air is greater than that of glass
           (c) density of glass is greater than that of-air
           (d) density of glass is less than that of air
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