Question

The rms value, of the electric field, in the em waves, produced a point source, at a distance of \((\frac{4}{\sqrt{\pi}})\) in from the point source, is 2V m^-1. Taking ε₀ = 8.85 x 10^-12 SI units and C = 3 x 108 ms^-1, we would find the power of the source to be (nearly)

(1) 2.3 nW

(2) 1.15 nW

(3) 2.3 pW

(4) 1.15 pW

Answer 1

(1) 2.3 nW

Let P be the power of the source. The intensity, at a distance \((\frac{4}{\sqrt{\pi}})\)m is then