Q

# In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 1010 Hz and amplitude 48 V m–1.Show that the average energy density of the E field equals the average energy density of the B field.

10.(c) In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of $2.0 \times 10 ^{10} Hz$  and amplitude $48 V m^{-1}$.

Show that the average energy density of the E field equals the average energy density of the B field. $[c = 3 \times 10^8 m s^{-1}. ]$

Views

The average energy density of the Electric field(UE

$\frac{1}{2}\epsilon E^{2}$

=$\frac{1}{2}\epsilon (Bc)^{2}$                 (as E=Bc)

=$\frac{1}{2}\epsilon \frac{B^{2}}{\mu \epsilon }$                      $(c=\frac{1}{\sqrt{\mu \epsilon }})$

=U

Therefore the average energy density of the electric field is equal to the average energy density of the Magnetic field.

Exams
Articles
Questions