Question

A helium–neon laser emits a beam of circular cross section with a radius r and a power P.?. (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 c.)(c) Find the momentum carried by a length of the beam. (Use the following as necessary: P, l, and c.)

Answer 1

there is a relation between intensity of light beam and the magnitude of electric field.I=(1/2)cϵonE2=P/πr2 E2=2P/cϵonπr2 E= magnitude of electric field n= refractive index of medium μoϵ0=1/c2
energy= power*time = P*(1m/speed of light)energy=(P∗1m)/c