Question

In an electromagnetic wave, the electric field of amplitude 4 V/m is oscillating. The Energy density of the wave is ___________

(a) 1.41 X 10^-10 J/m^3

(b) 2.41 X 10^-10 J/m^3

(c) 3.41 X 10^-10 J/m^3

(d) 4.41 X 10^-10 J/m^3

Answer 1

Right option is (a) 1.41 X 10^-10 J/m^3

Best explanation: We know, Energy density = ε E^2

Here, Emax = 4 V/m and ε = 8.85 X 10^-12 C^2/Nm^2

Therefore, Energy Density = 8.85 X 10^-12 X 4 X 4

= 1.41 X 10^-10 J/m^3.