Tue July 19, 2011 By:

Define 1 m and 1 sec in terms of wavelength.

Expert Reply
Mon July 18, 2011
One metre is defined as to be equal to 1,650,763.3 wavelengths in vacuum of the radiation emitted due to transition between the levels 2p10 and 5d5 of the isotope of Krypton having mass number 86.
One second is defined as to be equal to the duration of 9,192,631,770 vibrations corresponding to the transition between two hyperfine levels of Cesium-133 atom in the ground state.
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