UPSC 2000 › Science & Technology › Physics
8 questions · 2000 · answers as per the UPSC key
Which one of the following does a TV remote control unit use to operate a TV set?
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A noise level of 100 decibels would correspond to
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Fluorescent tubes are fitted with a choke. The choke coils
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When a CD (Compact Disc used in audio and video systems) is seen in sunlight, rainbow-like colours are seen. This can be explained on the basis of the phenomenon of
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Assertion (A): A man standing on a completely frictionless surface can propel himself by whistling.
Reason (R): If no external force acts on a system, its momentum cannot change.
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Assertion (A): In a motion picture, usually 24 frames are projected every second over the whole length of the film.
Reason (R): An image formed on the retina of eye persists for about 0.1 s after the removal of stimulus.
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Assertion (A): Small glass beads fixed on traffic signals glow brightly when light falls upon them.
Reason (R): Light is totally reflected when the angle of incidence exceeds a certain critical value and light travelling in a denser medium is reflected back into a rarer medium.
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Assertion (A): Large cold storage plants use ammonia as refrigerant while domestic refrigerators use chlorofluorocarbons.
Reason (R): Ammonia can be liquified at ambient temperatures at low pressures.