A laser with a power of 1.0 mW has a beam radius of 1.0 mm. What is the peak value of the electric field in that beam?
A)490 V/m
B)840 V/m
C)65 V/m
D)120 V/m
E)22 V/m

Question

Quizplus · Accepted Answer

The intensity (I) of the laser beam can be calculated using the formula I = P/A, where P is the power and A is the area of the beam. The area A = πr², where r is the radius. The intensity is related to the peak electric field (E) by the formula I = (1/2)ε₀cE², where ε₀ is the permittivity of free space and c is the speed of light. Solving for E gives the peak electric field value.

A Laser with a Power of 1