1. Dec 26, 2014 #1

   Garrulo

   

   How are G, ħ & c measured??

    

   Garrulo, Dec 26, 2014
2. 
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3. Dec 26, 2014 #2

   PAllen

   

   Science Advisor

   Gold Member

   Did you make any attempt to answer this on your own? As shown by the most trivial look up, you find that c is defined (not measured), and the measures of the others are described as below:
   
   http://en.wikipedia.org/wiki/Speed_of_light
   http://en.wikipedia.org/wiki/Gravitational_constant#History_of_measurement
   http://en.wikipedia.org/wiki/Planck_constant#Determination
   
   All of them may considered defined in some systems of units (for example, G is simply defined as 1 in some unit systems).

    

   Last edited: Dec 26, 2014

   PAllen, Dec 26, 2014
4. Dec 26, 2014 #3

   mfb

   

   Insights Author

   2016 Award

   Staff: Mentor

   Wikipedia and Google are better starting points for basic question like this.

    

   mfb, Dec 26, 2014

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