Electromagnetic Radiation, (radio waves, light, UV,etc.) occurs whenever you have an oscillating magnetic field (B) or an oscillating electric field (E). The oscillating B field will induce an E field that is oriented at 90° to the B field and is also 90° out of phase. That is, the largest E field occurs when the B field is changing the fastest which occurs when its amplitude crosses zero. Likewise, the B field induced by the changing E field is at its maximum when the E field amplitude is crossing zero. The B and E fields will continue to oscillate back and forth at right angles to each other. This oscillating electromagnetic field will propagate at the speed of light (c) in the direction orthogonal (perpendicular) to both fields.
page revision: 1, last edited: 22 Apr 2008 17:13