An electromagnetic wave of frequency 5 GHz, is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are 2. Its velocity in this medium is ____________ $\times$ 107 m/s.
Answer (integer)
15
Solution
Given, $\mu$<sub>r</sub> = $\varepsilon$<sub>r</sub> = 2<br/><br/>where, $\mu$<sub>r</sub> is relative permeability, $\varepsilon$<sub>r</sub> is relative permittivity.<br/><br/>Speed of electromagnetic wave v is given by<br/><br/>$v = {c \over n}$<br/><br/>where, n = refractive index = $\sqrt {{\mu _r}{\varepsilon _r}} = \sqrt 4 = 2$<br/><br/>$\Rightarrow v = {{3 \times {{10}^8}} \over 2}$ = 15 $\times$ 10<sup>7</sup> m/s<br/><br/>$\because$ x $\times$ 10<sup>7</sup> = 15 $\times$ 10<sup>7</sup><br/><br/>$\Rightarrow$ x = 15
About this question
Subject: Physics · Chapter: Electromagnetic Waves · Topic: Properties of EM Waves
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