The speed of an electromagnetic wave in a med | vedclass

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(D) The speed of an electromagnetic wave in a medium is given by the formula $v = \frac{1}{\sqrt{\mu \varepsilon}}$,where $\mu = \mu_0 \mu_r$ and $\va

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$1$

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(D) The speed of an electromagnetic wave in a medium is given by the formula $v = \frac{1}{\sqrt{\mu \varepsilon}}$,where $\mu = \mu_0 \mu_r$ and $\varepsilon = \varepsilon_0 \varepsilon_r$.Substituting these,we get $v = \frac{1}{\sqrt{\mu_0 \mu_r \varepsilon_0 \varepsilon_r}} = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} 	imes \frac{1}{\sqrt{\mu_r \varepsilon_r}}$.Since the speed of light in vacuum is $c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} = 3 	imes 10^8 \, m/s$,we have $v = \frac{c}{\sqrt{\mu_r \varepsilon_r}}$.Given $\varepsilon_r = 2.25$ and $\mu_r = 4$,we calculate the denominator: $\sqrt{2.25 	imes 4} = \sqrt{9} = 3$.Therefore,$v = \frac{3 	imes 10^8}{3} = 1 	imes 10^8 \, m/s$.The correct option is $D$.

The speed of an electromagnetic wave in a medium (whose dielectric constant is $2.25$ and relative permeability is $4$) is equal to .......... $\times 10^8 \, m/s$.

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