Poynting vectors S is defined as a vector whose magnitude is equal to the wave intensity and whose direction is along the direction of wave propagation. Mathematically, it is given by Show the nature of S vs t graph.

Question

Philoid · Accepted Answer

Let the electric and magnetic field by given by equations:

respectively.

Hence, the Poynting vector

Where θ is the angle between the two vectors, and for an electromagnetic wave since the two vectors are always perpendicular, we have θ = 90°,

Hence, S vs t graph is as follows,