To find the dimensional formula of Planck's constant (h), let's start with the given equation:
E = hν
Where:
E is the energy of the photon
h is Planck's constant
ν is the frequency of the radiation
Now, let's analyze the dimensions of each term.
Energy (E): The dimension of energy is given by the formula for kinetic energy or potential energy:
[E] = [M L² T⁻²]
(where M is mass, L is length, and T is time).
Frequency (ν): Frequency is the number of cycles per unit time, so the dimension of frequency is:
[ν] = T⁻¹
Now, substituting the dimensions of energy (E) and frequency (ν) into the equation E = hν:
[M L² T⁻²] = [h] × [T⁻¹]
To isolate the dimension of h, we divide both sides of the equation by T⁻¹:
[h] = [M L² T⁻²] × T
[h] = [M L² T⁻¹]
Thus, the dimensional formula of Planck's constant (h) is:
[M L² T⁻¹]