Question

why is h=6.63*10^-34 Js?
Any derivation?

Answer 1

it's derived from empirical evidence when the linear and proportional relationship between the energy in electromagnetic radiation and frequency was measured - with the proportionality constant equal to 6.626*10^-34 Js

http://physics.info/planck/

Answer 2

The first value for constant h, were obtained by the same M. Planck, using the available experimental data. The value obtained by M. Planck, in the far 1901, was:
\[\Large h = 6.55 \times {10^{ - 27}}erg \cdot \sec \]
here is the source:
\[\large \begin{gathered}
{\text{M}}{\text{. Planck}}{\text{, Annalen der Physik (Lipsia) }}{\mathbf{4}}{\text{, 564 }}\left( {{\text{1901}}} \right); \hfill \\
Abhandlungen,{\text{ Vol}}{\text{. 1}}{\text{, pag}}{\text{. 728}}{\text{.}} \hfill \\
\end{gathered} \]

Answer 3

@Michele_Laino @aaronq
Thank you for the info, I will look into that. But can you guys give some video link to understand nicely

Answer 4

@Robert136
need video link for this

Answer 5

This one is detailed derivation of plank's constant.
https://www.youtube.com/watch?v=syQbWP-7WC4

Answer 6

Will see that...

Answer 7

@Abhisar. I want why h=6.63*10^-34
I don't want Planks law!
See on that if you can

Answer 8

Actually I got it why h=6.64*10^-34
.
Anyway thanks for trying....

Answer 9

That's a very beautiful website which you gave
@aaronq