A helium-neon laser intended for instructional use operates at 3.7 mW. a) Determ

Question

A helium-neon laser intended for instructional use operates at 3.7 mW.



a) Determine the maximum value of the electric field at a point where the cross sectional area of the beam is 1.3 mm2. Answer in units of V/m.

(I got the answer as 1448.29 V/m after using the equation E = sqrt(P*2Uc/A), but this answer appears to be incorrect)



b)Calculate the electromagnetic energy in a 1.5 m length of the beam.

(I got the answer 1.85*10^(-11) and this appears to be incorrect)



*Please answer both sub parts of the question.

Explanation / Answer

We know that I = P / A = E^2 / c uo ==> E = [P c uo / A ]^1/2 = [ 3.7 x 10^-3 * 3 x 10^8 * 4 * 3.17 x 10^-7 / 1.3 x 10^-6 ] ^1/2 = 1.0355 x 10^3 V/m = 1035.5 V/m

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.