Dimensional formula of Photon momentum

How to get the dimensional formula of photon momentum

1. Start from the definition: photon momentum = plancks constant / wavelength.
2. velocity = length / time, so velocity is [L] / [T] = [L T^-1].
3. energy = mass × velocity², so energy is [M] × [L T^-1]² = [M L² T^-2].
4. Planck's constant = energy × time, so Planck's constant is [M L² T^-2] × [T] = [M L² T^-1].
5. wavelength = length, so wavelength is [L] = [L].
6. Put in the dimension of each part: [M L² T^-1] / [L].
7. Add the powers of each base quantity: [M L T^-1].

Quantities with the dimensions [M L T⁻¹]

• Momentum
• Impulse

Equal dimensions do not make them the same quantity. Compare photon momentum with the others in the full grid.

Three questions on photon momentum

Related quantities

• φ₀ Work function [M L² T⁻²]
• E Photon energy [M L² T⁻²]
• λ de Broglie wavelength [L]
• V₀ Stopping potential [M L² T⁻³ A⁻¹]
• λ Decay constant [T⁻¹]
• R Activity [T⁻¹]