If an optical medium possesses a relative permeability of 10/π and relative permittivity of 1/0.0885 , then the velocity of light is greater in vacuum than that in this medium by times. (μ 0 =4 π × 10 -7 H / m , in 0 =8.85 × 10 -12 F / m . , c=3 × 10 8 m / s )

Physics · Electromagnetic Waves

JEE Main 2025 — 4 April, Evening Shift — Question 63

If an optical medium possesses a relative permeability of $\frac{10}{\pi}$ and relative permittivity of

$\frac{1}{0.0885}$ , then the velocity of light is greater in vacuum than that in this medium by

$\qquad$ times. $\left(\mu_{0}=4 \pi \times 10^{-7} \mathrm{H} / \mathrm{m}, \in_{0}=8.85 \times 10^{-12} \mathrm{~F} / \mathrm{m}\right.$ ,

$c=3 \times 10^{8} \mathrm{~m} / \mathrm{s}$ )

Numerical answer — enter this value.

$\mu_{r}=\frac{10}{\pi} \quad \epsilon_{r}=\frac{1}{0.0885}$

$c=\frac{1}{\sqrt{\mu_{0} \in_{0}}}$

$v=\frac{1}{\sqrt{\mu_{r} \mu_{0} \in_{r} \in_{0}}}=\frac{1}{\sqrt{\mu_{r} \in_{r}}} c$

$v \simeq \frac{C}{6}$ $c \simeq 6 v$

Answer key and solution verified before publishing.

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