obtain an expression for the energy density of an electromagnetic wave .Inthe electromagnetic wave show that the average energy density of the electric field equals the average energy density of the magnetic field?

Dear student,

The energy in an electromagnetic wave is tied up in the electric and magnetic fields. In general, the energy per unit volume in an electric field is given by:

UE=12ε0E2

In a magnetic field, the energy per unit volume is:

UB=12μ0B2

An electromagnetic wave has both electric and magnetic fields, so the total energy density associated with an electromagnetic wave is:

U= 12ε0E2+12μ0B2
 

It turns out that for an electromagnetic wave, the energy associated with the electric field is equal to the energy associated with the magnetic field, so the energy density can be written in terms of just one or the other:

U=ε0E2=1μ0B2

UE=12ε0E2 and UB=12μ0B2
E=cBE=1ε0μ0BE2=1ε0μ0B212ε0E2=B22μ0
Hence the two energies are equal
 

Hope this information will clear your doubts about topic.

If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.

 

Regards

 


 


 

  • 2
What are you looking for?