# Can someone tell me planck constant?

Every time i see it it's different. I want the full planck constant(every number) and is there any proof for the constant?

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The Planck constant is:
6.63 x 10^-34 J•s

The symbol is "h". You will have different values depending on the units used. For example, Planck Constant is also:

4.135667516(91) x 10^-15 in eV•s

There are various proofs of the constant on the internet. A lot of the ones I see are experimental proofs.

Simon Bridge
Homework Helper
Every time i see it it's different. I want the full planck constant(every number) and is there any proof for the constant?
Nobody can comply with your request because nobody knows every digit - nobody can measure that accurately.
You can look up the standard value online. I don't know of sources disagreeing, can you supply an example?
There are many proofs for the constant - you can look those up too.
Do you have reason to suspect that it may not be?

Uh OK - in SI units: 6.62606957 × 10-34 m2 kg / s But in unified units it is 1.
So, in that sense, you can know every digit ...

AS for proofs - see:
http://iopscience.iop.org/0034-4885/76/1/016101

Nobody can comply with your request because nobody knows every digit - nobody can measure that accurately.

You can look up the standard value online. I don't know of sources disagreeing, can you supply an example?

There are many proofs for the constant - you can look those up too.

Do you have reason to suspect that it may not be?

Ah I missed the "whole digit thing". Yeah, I agree with Simon! There isn't someone who actually knows every digit of the Planck constant.

Thank you all for the answers

ZapperZ
Staff Emeritus