A plane electromagnetic wave travels in a medium of relative permeability 1 . 61 and relative permittivity 6 . 44 . If magnitude of magnetic intensity is 4 . 5 × 10 - 2 A m - 1 at a point, what will b

Question

A plane electromagnetic wave travels in a medium of relative permeability $1.61$ and relative permittivity $6.44$ . If magnitude of magnetic intensity is $4.5 \times 10^{- 2} A m^{- 1}$ at a point, what will be the approximate magnitude of electric field intensity at that point ?

(Given : Permeability of free space $μ_{0} = 4 π \times 10^{- 7} N A^{- 2}$ , speed of light in vacuum $c = 3 \times 10^{8} {m s}^{- 1}$ )

TestHub · Accepted Answer

The speed of light in a given medium is given by,

$v = \frac{c}{\sqrt{μ_{r} ε_{r}}}$

Magnetic field is $B = μ_{r} μ_{0} H$ .

Also, the relation between the magnetic field and electric field is given by,

$E = v B \Rightarrow E = \frac{c}{\sqrt{μ_{r} ε_{r}}} \times μ_{r} μ_{0} H = \frac{c}{\sqrt{ε_{r}}} \times \sqrt{μ_{r}} \times μ_{0} H \Rightarrow E = \frac{3 \times 10^{8}}{\sqrt{6.44}} \times \sqrt{1.61} \times 4 π \times 10^{- 7} \times 4.5 \times 10^{- 2} = 8.48 V m^{- 1}$

Physics - EM Waves Question with Solution | TestHub

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