Electromagnetic waves | Physics | Khan Academy

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Electromagnetic (EM) waves are produced whenever electrons or other charged particles accelerate. The wavelength of an EM wave is the distance between consecutive points on the wave with the same phase (e.g. one crest to the next crest). The frequency of an EM wave is how many wave cycles are emitted, or pass a given point, per second. The speed of a wave is equal to its frequency times its wavelength. In vacuum, all EM waves travel at speed c = 3 x 10^8 m/s.

Sections:
00:00 - Intro
00:19 - What is an EM wave?
00:46 - How are EM waves created?
02:15 - Amplitude and phase
04:26 - Wavelength and frequency
06:00 - Wave speed
08:01 - Speed of EM waves in vacuum
09:09 - The EM spectrum
10:26 - Analog modulation
12:58 - Digital modulation

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