Orange light emitted from krypton-86 atoms was used to define:
Correct answer: B. Meter
- A. Kilogram
- B. Meter
- C. Centimetre
- D. Second
Explanation
The meter is defined in terms of the speed of light in a vacuum (c) and the duration of a specific number of oscillations of a cesium-133 atom. However, before the current definition, the meter was initially defined by a prototype physical object, the International Prototype of the Meter, and later by the wavelength of the orange light emitted by krypton-86 atoms. The current definition based on the speed of light was adopted to provide a more stable and precise standard.
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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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