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8.Electromagnetic waves
hard
Electromagnetic waves travel in a medium with speed of $1.5 \times 10^8 \mathrm{~ms}^{-1}$. The relative permeability of the medium is $2.0$ . The relative permittivity will be :
A
$5$
B
$1$
C
$4$
D
$2$
(JEE MAIN-2024)
Solution
$\frac{\varepsilon_{\mathrm{II}} \times \mu_{\mathrm{mL}}}{\varepsilon_0 \times \mu_0}=\frac{\frac{1}{\mathrm{v}^2}}{\frac{1}{\mathrm{c}^2}}$
$\varepsilon_{\mathrm{r}} \times \mu_{\mathrm{r}}=\frac{\mathrm{c}^2}{\mathrm{v}^2}$
$\varepsilon_{\mathrm{r}} \times 2=\frac{\left(3 \times 10^8\right)^2}{\left(1.5 \times 10^8\right)^2}$
$\varepsilon_{\mathrm{r}} \times 2=4$
$\varepsilon_{\mathrm{r}}=2$
Standard 12
Physics
