
#1
Feb407, 01:19 PM

P: 9

c is 299 792 458 m/s without uncertainty? doesn't work the Heisenberg uncertainty principle for fotons?




#2
Feb407, 02:08 PM

P: 290

The distances typically involved in measuring c are sufficently big that quantum fluctuations are ignored.
Also, the length of 1m is defined by the distance light travels in a certain amount of time. Because of this definition, we're effectively defining light's speed, not measuring it, so it is exact. 



#3
Feb507, 07:24 AM

P: 80





#4
Feb507, 12:14 PM

Mentor
P: 22,001

c = 299 792 458 m/s and uncertainty
No, the meter is defined as the distance light travels in a specified time.
http://www.mel.nist.gov/div821/museum/timeline.htm 


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