In a plane electromagnetic wave,which of the | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) In a plane electromagnetic wave,the electric field $\vec{E}$ and magnetic field $\vec{B}$ are represented by sinusoidal functions,such as $\vec{E}

Vedclass · Accepted Answer

$(a), (c)$

Vedclass · Answer

(A) In a plane electromagnetic wave,the electric field $\vec{E}$ and magnetic field $\vec{B}$ are represented by sinusoidal functions,such as $\vec{E} = E_0 \sin(kx - \omega t)$ and $\vec{B} = B_0 \sin(kx - \omega t)$.The average value of a sine or cosine function over one complete cycle is zero. Therefore,the average values of the electric field $\vec{E}$ and the magnetic field $\vec{B}$ are zero.However,the energy densities associated with these fields are proportional to the squares of the fields ($U_E \propto E^2$ and $U_B \propto B^2$). Since the square of a sine function is always non-negative,the average value of electric energy and magnetic energy over one complete cycle is non-zero.Thus,only the electric field and the magnetic field have a zero average value over one complete cycle.

In a plane electromagnetic wave,which of the following has/have a zero average value in one complete cycle?
$(a)$ Magnetic field
$(b)$ Magnetic energy
$(c)$ Electric field
$(d)$ Electric energy

Similar Questions

The speed of electromagnetic waves is the same for .......

When an electromagnetic wave passes through a dielectric medium,the transmitted wave has:

In the given electromagnetic wave $E_y = 600 \sin (\omega t - kx) \ Vm^{-1}$,the intensity of the associated light beam is (in $W/m^2$); (Given $\epsilon_0 = 9 \times 10^{-12} \ C^2 N^{-1} m^{-2}$ and $c = 3 \times 10^8 \ m/s$)

If ${\mu_r}$ is the relative permeability and $K$ is the dielectric constant of a medium,its refractive index $n$ is given by:

The frequency of an electromagnetic wave is $25 \ MHz$. If the magnitude of the electric field at a point at any instant is $6.3 \ V/m$,then the magnitude of the magnetic field at that point is ..... $Wb/m^2$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module

In a plane electromagnetic wave,which of the following has/have a zero average value in one complete cycle?$(a)$ Magnetic field$(b)$ Magnetic energy$(c)$ Electric field$(d)$ Electric energy