What is radio wave and how is radio wave produced?

[aditya2303]

was hoping for a video

[jimqbaum]

Yep, some can teach and some can show. Showing is not teaching.

[alove23023]

i like the music...

[MJorgealdo]

Isnt the magnetic field created when eletrically charged particles are on move ?

[crystalnjohn06]

i dis like because youtube is for video if i wanted to read it i would use wiki. stop being a dummy!

[saggoh]

Thanks this was amazing.

[lastnameavailableok]

music is haunting. Where I get soundtrack to this fillum?

[Khalid2222a]

An oscillating electric current creates an oscillating electric field; the oscillating electric field creates and oscillating magnetic field, this is govern by maxwell's equations. Hence, AC current is needed to create electromagnetic waves. However, DC current only creates electromagnetic fields.

[1arithehun]

@Khalid2222a Makes sense. Thanks for getting that point out there, it's so easy to only think about electricity in DC.

[sspoke]

how do wifi antennas make Direct connections with only my antenna and not other metallic objects or antennas.. that hasn't been explained here. As well as if radio waves travel endlessly how come I aint getting signals from the past? (old radio waves) only current ones can't explain that one can you? of course not, only explanation is a direct connection is formed, similar to any type of wires if you cut it, connection is lost.. only this connection is very slim and microscopic.

[xavioe63]

Hope you can prove than radio waves propagates in a speed of 3e8 m/s which is (1/electric permittivity* magnetic permeability)^1/2

[bhongusa]

This is why good electric conductors are ideal as reflective surfaces when constructing waveguides and transmission lines.

Back to the concept of generating electromagnetic waves, a conductor is necessary to establish an oscillating separation of charge and an oscillating current which create the initial source field. This is how antennas and transmission lines radiate electromagnetic waves.

Finally, the speed of an electromagnetic wave in free space is the speed of light, c = 3e8 m/s.

[bhongusa]

Whenever the sources that generate electric fields oscillate with time though (dipole antennas or AC sources), we observe time harmonic electromagnetic fields (electromagnetic waves) that can exist within free space. If you meant that electromagnetic waves could not be generated without a conductor, you are somewhat correct. But the waves themselves can propagate anywhere.

Interestingly, perfect electric conductors do not allow for any sort of field to be established within them.

[bhongusa]

Maxwell's equations tell us that within any medium or free space,

1) Electric charge creates divergent electric fields. (Gauss's Law)

2) Divergent magnetic fields cannot exist because there are no magnetic monopoles. (Gauss's Magnettism Law)

3) Electric current (moving charge) creates solenoidal magnetic fields. (Ampere's Law)

4) A changing electric field creates solenoidal magnetic fields. (Displacement Current)

5) A changing magnetic field creates solenoidal electric fields. (Induction)

[bhongusa]

Are you arguing that electromagnetic waves cannot propagate in free space? Maxwell's conclusions have no mistakes; his equations form the basis of electromagnetics and electrical engineering. If waves could not propagate in free space, how would light propagate? How do satellite and radar communication systems operate? Signals are sent into space and received halfway around the world! His findings have been verified to be valid within free space (vacuum) and any medium, conductive or not.

[easternmafia]

witout the music!

[TheCombineify]

Hi, i like the music and your vid :)

but wats the music

[CanyonLakeTX]

Love your work, Thank you for helping me understand the physics of EMF>R

[807004407]

i think this music puts people to sleep while not allowing them to focus on the information...please review music and put some graphical aids

[gmcjetpilot]

You have some English issues, PM me if you want me to proof read next time..... Good video. I have degrees in mechanical engineering and physics and mathematics. My hobby is radio, repair, operation, experimentation. This is a good explanation of the relationships of current, magnetic fields and RF (electromagnetic radiation - non ionizing of course) Radio Freq propagation. You can spend a lot of enjoyable time in this field.

[ptmonyxIL]

Should have graphics and other media to get the point across!

[upsilon054]

@ptmonyxIL Well, okay, maybe. But I will say this much. I remember my introductory college physicsc classes from 1973-74, when there was no Internet or YouTube;. This is light years better than listening to some tired old professor counting the days until retirement. Physics for me didn't get interesting until I took quantum mechanics. Now THAT was a wonderful class, and we had a very dynamic professor. Professor Gloria Hoff, if you read this, note that you did a wonderful job!

[gizmoguyar]

Hey I like the music, what is it?

[otivaeey]

you really need graphics or video animations instead of piling up words to do a successful presentation.