The standard of time in SI system is the clock of:
Correct answer: C. Cesium
- A. Uranium
- B. Rubidium
- C. Cesium
- D. Radium
Explanation
The definition of a second in the SI system is based on the properties of cesium atoms. It's determined by the frequency of radiation that cesium atoms emit when transitioning between two specific energy levels. This consistent and precise measurement of atomic vibrations forms the basis for the standard unit of time, ensuring worldwide uniformity and accuracy.
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About Measurements
Physical quantities are expressed with SI base and derived units, while measurement limits are described through accuracy, precision, absolute and percentage error, and significant figures. Dimensional analysis checks equations, derives relationships and detects inconsistent units, but it cannot determine numerical constants or distinguish quantities with identical dimensions.
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