1. The problem statement, all variables and given/known data Prove that the relationship between the dimensionless amplitude a of a wave and the intensity I of the wave is given by: 2. Relevant equations B = curl (A) B: Magnetic Field A = [mass of electron * c / e ]*a*e^[i*(kx-wt)] where k is the wavenumber and is given by: 2pi / wavelength of laser I = c*B^2 / (magnetic permeability of free space) Hint: div(A) = 0 will give a unique solution for B 3. The attempt at a solution Honestly I do not know where to begin. Take the divergence of the equation of A and find a solution for B? I am not sure.