A sinusoidal electromagnetic wave with an electric field amplitude of 100 V/m is incident normally on a surface with an area of 1 cm² and is completely absorbed.The energy absorbed in 10 s is: A)1.3 mJ B)13 mJ C)27 mJ D)130 mJ E)270 mJ

Question

Quizplus · Accepted Answer

The intensity (I) of the wave is given by I = (E^2)/(2μ₀c), where E is the electric field amplitude, μ₀ is the permeability of free space, and c is the speed of light. Substituting E = 100 V/m, μ₀ = 4π x 10^-7 T·m/A, and c = 3 x 10^8 m/s, we find I = 13.3 W/m². The area is 1 cm² = 1 x 10^-4 m², so the power absorbed is 1.33 x 10^-3 W. Over 10 seconds, the energy absorbed is 13.3 x 10^-3 J = 13 mJ.

A Sinusoidal Electromagnetic Wave with an Electric Field Amplitude of 100