Question

which formula is used to find fluctuation of the size of a body

Answer 1

Answer:

the wave-interaction noise term of Einstein's formula for the fluctuation in the number of quanta received from a black-body radiator.

var n=n~1+1ehvk T-1

Is verified by the splitting the beam and

correlating the photodetector noise currents.This technique eliminates the shot noise and measures the wave-interaction noise directly.

Good agreement between theory and experiment is obtained when the effects of optical losses and the wave length dependence of the optical filter and taken into account...

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