Question

If a beam of electromagnetic radiation has an intensity of 140 W/m², what is the maxiμm value of the electric field? (C

a) 5 V/m
b) 10 V/m
c) 15 V/m
d) 20 V/m

Answer 1

The maximum value of the electric field for an electromagnetic radiation beam with an intensity of 140 W/m² is approximately 17.3 V/m, which is closest to the given option (c) 15 V/m.

Step-by-step explanation:

If a beam of electromagnetic radiation has an intensity of 140 W/m², we can use the relationship between the intensity (I) and the peak electric field (Emax) in an electromagnetic wave given by the formula I = ½ ε0 c Emax², where ε0 is the permittivity of free space (ε0 = 8.85 × 10-12 C²/N·m²) and c is the speed of light (c = 3 × 108 m/s). Solving for Emax, we find Emax = √(2I / (ε0 c)). Substituting I = 140 W/m² into the equation, we get Emax = √(2 × 140 W/m² / (8.85 × 10-12 C²/N·m² × 3 × 108 m/s)). After calculating, we get the maximum value of the electric field, which is approximately 17.3 V/m. This is closest to option (c) 15 V/m.