Ahelium–neon laser emits a beam of circular cross section with a radius r and a power (a) find the maximum electric field in the beam. (use any variable or symbol stated above along with the following as necessary: μ0 and c.. (b) what total energy is contained in a length of the beam? (use the following as necessary: p, l , and ) find the momentum carried by a length of the beam. (use the following as necessary: p, l, and c.)