Multiple choice

Consider the following statements regarding the complex Poynting vector $\overrightarrow{P}$ for the power radiated by a point source in an infinite homogeneous and lossless medium Re $(\overrightarrow{P})$ denotes the real part of $\overrightarrow{P}$. S denotes a spherical surface whose centre is at the point source, and $\hat{n}$ denotes the unit surface normal on S. Which of the following statements is TRUE?

  1. Re $(\overrightarrow{P})$ remains constant at any radial distance from the source
  2. Re $(\overrightarrow{P})$ increases with increasing radial distance from the source
  3. _ $∯_s Re$$(\overrightarrow{P})$.$\hat{n}$dS remains constant at any radial distance from the source
  4. $∯_s Re$$(\overrightarrow{P})$.$\hat{n}$dS decreases with increasing radial distance form the source
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Powe radiated from any source is constant.

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