Correct Answer - Option 2 : 1 × 10
-15
CONCEPT:
- To measure time, we use the atomic standard of time that is based on periodic vibrations produced in a cesium atom.
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Cesium clock: It is used at National Physical Laboratory, New Delhi to maintain the Indian standard of time.
- It is also called the atomic clock.
- The vibrations of the cesium atom regulate the rate of the cesium atomic clock.
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Cesium atomic clocks provide very high accuracy.
EXPLANATION:
- The uncertainty imparted in time realization is ± 1 × 10-15, e., one part in 10-15.
Hence option 2) is correct.