radio waves

[bhuvanesh]

while watching video i have seen this statement "oscillating electric field oscillating magnetic field not electromagnetic wave"i dont understand what he really mean.thank you

 

[(*steve*)]

Without context, I doubt anyone else does either.

 

[bhuvanesh]

sorry

while watching video i have seen this statement "oscillating electric field create oscillating magnetic field, not electromagnetic wave"i dont understand what he really mean.thank you

 

[davenn]

AN oscillating electric field creates AN oscillating magnetic field

my bold added for clarity
Yes that is correct ... but it goes further
an oscillating electric field creates an oscillating magnetic field, which creates an oscillating electric field
over and over ... result ... a electromagnetic field

BUT NOTE it can start the other way as well
an oscillating magnetic field creates an oscillating electric field which creates an oscillating magnetic field... etc etc

result = still an electromagnetic field

( as far as I'm aware ) One cannot exist without the other


Dave

 

[(*steve*)]

"not an electromagnetic wave" is an interesting statement, because in that case he must mean you're creating low energy photons.

 

[Arouse1973]

Unfortunately you don't have a choice in free air whether an EM wave is generated or not when you have a changing magnetic and electric field. They go hand in hand as Dave said. It depend on where you interact with these fields which matters.

The EM wave is generated in the transition region between near field and far field, you don't have a choice about that. Electric fields and magnetic can exist in there own right in the reactive field and have different phases and magnitudes but they will always appear together if they are going to create an EM wave. Unlike triobo-electric charging which can have an electric field without a magnetic field but this is a static field.

Adam