# The Significance of the Poynting Vector

We can multiply an electric field by a magnetic field to obtain the Poynting vector, S = E×H, and the product applies to the energy flow in electromagnetic radiation, where E is specifically an electric field that has been induced by time-varying electromagnetic induction. This is because the form of the Poynting vector follows from Ampère’s circuital law and Faraday’s law of time-varying electromagnetic induction. Although there is no known theoretical basis that would justify swapping the electromagnetic E field in S with an electrostatic E field, the dimensions of S would nevertheless remain unchanged if we did do so. As such, it has been asked whether or not the product E×H is predictive of any energy flow when an electrostatic field is superimposed upon a steady state magnetic field, or would it just amount to multiplying apples and bananas? Click on this link, https://www.researchgate.net/publication/338898407_The_Significance_of_the_Poynting_Vector