The value of Planck's Constant

[Prina Patel 1H]

I don't understand how was the value of Planck's constant derived?

[TiffanyDinh1C]

Planck hypothesized that just like how water's smallest unit is a water molecule, energy also works the same way and can be expressed in discrete or "quantized" units. Therefore Planck's constant is used as a proportionality constant that links the particle's frequency of its electromagnetic wave to its total energy (E=hv) in order to come up with these "quantized units".

[Jake Ney lecture 1 discussion 1F]

Planck's constant was determined empirically as experiments relating frequency to energy reveal the value of this constant. If you were to plot a graph of energy versus frequency in which the y-axis was labeled Energy and the x-axis was labeled frequency you would get a straight line with a slope of 6.626x10^-34, which is Planck' constant.

[Masahiro Yabe 2H]

Planck's Constant was calculated from experimental data of E=hv. In this equation, the value of energy and frequency is directly proportional to each other. This is the same equation as y=mx where m is the slope. In the same way, the value of Planck's Constant represent the slope of energy vs. frequency graph. Therefore, by experimentally determining values of energy with frequencies (must be two or more of each), value of Planck's constant can be derived from h=(E2-E1)/(v2-v1).