Planck constant (h) is the proportianility constant between the energy (E) of an atomic oscillator and the frequency (f) of the associated electromagnetic wave.

The relation between energy and frequency was given by the famous equation:

E=hf

The unit of ‘h’ is expressed in joule seconds (J·s) or (N·m·s) which is quite unusual as it means the product of energy and time, which is difficult to interpret.

The reason for this is that frequency is given by a natural number divided by time (t), so ‘h’ must be multiplied by time (t) as the product must result energy.

h x t x n/t = E - in units: joule x sec x n/sec = joule

The other problem with Planck’s relation is that ‘h’ refers to energy change (W) so if we divide it by time, we get ‘power’ (P) not energy.

hn/t = W/ t = P

If we interpret the product of frequency and Planck’s constant what it is – that is Power- , we dissolve all problems:

P = hf - here the unit of ‘h’ is ‘joule’.

The meaning of the equation is: higher frequency has higher power instead of higher energy.

To transform power to energy we must multiply it by time.

dE = W = P dt = hf dt

So time becomes a factor of the equation, not a redundant element of unit.

Sandor Fofai