Electromagnetic wave frequency is low, mainly through the conductor will be delivered tangible

Electromagnetic wave frequency is low, mainly borrowed from the conductor to transfer tangible. The reason is that the low frequency circuit breakers, the magnetic interaction between the change is slow, almost all of the energy return of the original circuit without the energy radiated out; air circuit breaker high frequency which can be transmitted in free space, can also be bound in tangible conducting in vivo delivery. In free space mcb circuit breaker because the high frequency oscillations, the magnetic interaction becomes very fast, not all return to their original energy of the oscillator circuit, so electric, magnetic as the periodic variation of electric and magnetic fields in the form of electromagnetic waves into space spread out, no medium can pass out energy, which is a kind of radiation. For example, the distance between the Sun and the Earth is very far away, but when outdoors, we can still feel the warm sun light and heat, which is like a "phenomenon of electromagnetic radiation by the radiation energy transfer," the same principle.