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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I'm sure it's not just me, and that all of the fans of your videos on Khan Academy India and Float Head Physics are super excited to see you on the main Khan Academy channel!
Thank you for making our learning journeys so much more fun and congratulations! 🥳

ardrapattath
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very clear this explanation...thankyou...

zulyadein
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You made it easy to understand! thanks man!

Shaheen-VO
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Sir can you make a video explaining deeply what are changing electric field and magnetic field and why do change and don't require a medium to travel

mirhairref
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Woah, perfect explanation. Have a great day!

Wicked.-kczo
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I enjoyed this video and found it very informative. Thank you for keeping my brain active during the summer Khan! Also I love this instructor 🔥

geographynerd
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9:41 So does that mean we separate them by their frequency?

YaMinKyalSin
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These are the key points and you make so easy to understand 😊😊

RavalTanwar
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on an atomic level, why a moving charge produces magnetic field? and why these changing fields propagate? these are the basic physical questions you should have included too.

kaavyabanerjee
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@floatheadphysics
Can't believe that's you. Lots of love as you made my understanding of physics laws sublte not malicious.

MojeAdeyemo
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Information can be transmitted through all waves as long as the receiver can detect what the transmitter is sending! 😎🤖

thesimplicitylifestyle
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If electrons lose energy as they move as stated in 1:06, do wifi routers eventually stop working due to the electrons losing all of their energy?

itsjd
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Ref @4 minutes: Thought you had to have 2 waves to be able to talk about waves being in or out of phase with each other. How can 2 points be out of phase when they are just 2 points at different points in time within the cycle of a single wave?

zz
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Why does an electron oscillating up and down generate an electric field?

tangent