An electromagnetic wave with frequency 65.0Hz travels in an insulating magnetic material that has dielectric constant 3.64 and relative permeability 5.18 at this frequency. The electric field has amplitude 7.20×10−3V/m. What is the wavelength of the wave?

Answer :

Answer:

  The wavelength of the wave is [tex]1.06\times10^6 m[/tex]  

Explanation:

Lets calculate

We know an electromagnetic wave is propagating through an insulating magnetic material of dielectric constant K and relative permeability [tex]K_m[/tex] ,then the speed of the wave in this dielectric medium is [tex]\nu[/tex] is less than the speed of the light c and is given by a relation

               [tex]\nu=\frac{c}{\sqrt{KK_m} }[/tex]  --------- 1

In case the electromagnetic  wave propagating through the insulating magnetic material , the amplitudes of electric and  magnetic fields are related as -

             [tex]E_m_a_x= \nu B_m_a_x[/tex]

The magnitude of the 'time averaged value' of the pointing vector is called the intensity of the wave and is given by a relation

                       [tex]I = S_a_v[/tex]

                        [tex]\frac{E_m_a_xB_m_a_x}{2K_m\mu0}[/tex]----------- 3

now , we will find the speed of the propagation of an electromagnetic wave by using equation 1

[tex]\nu=\frac{c}{\sqrt{KK_m} }[/tex]

Putting the values ,

   =[tex]\nu= \frac{3.00\times10^8}{\sqrt{(3.64)(5.18)} }[/tex]

 =[tex]0.6908\times10^8m/s[/tex]

 = [tex]6.91\times10^7m/s[/tex]

Now , using this above solution , we will find the wavelength of the wave -

     [tex]\lambda=\frac{\nu}{f}[/tex]

    Putting the values from above equations -

  [tex]\frac{6.91\times10^7m/s}{65.0Hz}[/tex]

        [tex]\lambda= 1.06\times10^6 m[/tex]

Hence , the answer is [tex]\lambda= 1.06\times10^6 m[/tex]