Question

Maxwell postulated the existence of the displacement current as a way to resolve a mathematical inconsistency, even though there was no direct experimental evidence for it. Why was the displacement current so hard to detect? Can you think of any other successful physics predictions that were motivated by purely mathematical/aesthetic reasons?

Answer 1

Since displacement currents are not actual flow of electrical charges but a time varying electric field. So in order for measuring this current we can not connect a measuring device anywhere because field exists without medium also. This is the reason why it is difficult to measure unlike regular current.

The existence of black holes is another example. It was predicted by mathematical formulation that there can be a physical object which has escapevelocti morethan velocity of light. Later it is discovered