Answers

2015-08-03T17:57:46+05:30
Those clocks are known as Atomic Clocks.
Hope it helps and pls mark it as the best answer. :-)
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plzz mark mine as the best answer..
2015-08-03T18:09:21+05:30
i think answer is stop watch.
because u see in  running races or any races they used stop watch to measure the short time..

hope its help u..
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