The oscillating currents flowing around the cavities, and their effect on the electron flow within the tube, causes large amounts of microwave radiofrequency energy to be generated in the cavities.
12.
Since the velocity of propagation is very high about 300, 000 kilometers per second the wave of an alternating or oscillating current, even of high frequency, is of considerable length.
13.
Loosely, it states that the relationship between an oscillating current and the resulting electric field is unchanged if one interchanges the points where the current is placed and where the field is measured.
14.
When a high voltage from an induction coil was applied to one tuned circuit, creating sparks and thus oscillating currents, sparks were excited in the other tuned circuit only when the circuits were adjusted to resonance.
15.
When a high voltage from an induction coil was applied to one tuned circuit, creating sparks and thus oscillating currents, sparks were excited in the other tuned circuit only when the inductors were adjusted to resonance.
16.
Conversely, during reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the electrons in the antenna elements, causing them to move back and forth, creating oscillating currents in the antenna.
17.
The National Institutes of Health near Washington, D . C ., is developing an instrument that maps conductivity variations by passing an oscillating current through the body in a strong magnetic field, which creates detectable ultrasonic vibrations.
18.
Thus, the work of many researchers enabled the use of electronics to convert signals into high frequency oscillating currents, and via suitably shaped conductors, electricity permits the transmission and reception of these signals via radio waves over very long distances.
19.
When the integrals above are evaluated for typical cases, e . g . of an oscillating current ( or charge ), they are found to give both a magnetic field component varying according to " r " " 2 ( the induction field ) and a component decreasing as " r " " 1 ( the radiation field ).
