we can write in the solution of a nonhomogenuos equation as
u(x)=integral(g(x.x1)*f(x)dx...where f(x) is the sourse term...if sourse term is zero.ie homogenous equation,what will be the solution?zero?what it means?homogenous equation has no solution?
then in the series form of greens function...
electromagnetic field is a classical field or quantum field?in quantum we speak in erms of photons...if we go for second quantisation to electromagnetic field what we will get??