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3 questions · 1998 · answers as per the UPSC key
UPSC 1998 · Q108 · Science & Technology › Physics · Save
A fuse is used in main electric supply as a safety device.
Which one of the following statements about the fuse is correct?
(a) It is connected in parallel with the main switch
(b) It is made mainly from silver alloys
(c) It must have a low melting point
(d) It must have a very high resistance
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Answer: (c) It must have a low melting point
UPSC 1998 · Q114 · Science & Technology › Physics · Save
A ball is dropped from the top of a high building with a constant acceleration of 9.8 m/s². What will be its velocity after 3 seconds?
(a) 9.8 m/s
(b) 19.6 m/s
(c) 29.4 m/s
(d) 39.2 m/s
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Answer: (c) 29.4 m/s
UPSC 1998 · Q128 · Science & Technology › Physics · Save
Assertion (A): The temperature of a metal wire rises when an electric current is passed through it.
Reason (R): Collision of metal atoms with each other releases heat energy.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is NOT a correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
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Answer: (c) A is true, but R is false