A plane electromagnetic wave travels in a medium of relative...

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

$v = \dfrac{c}{\sqrt{{\mu}_{r}{ε}_{r}}}$

Magnetic field is $B = {\mu}_{r}{\mu}_{0}H$.

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

$E = vB ⇒ E = \dfrac{c}{\sqrt{{\mu}_{r}{ε}_{r}}} \times {\mu}_{r}{\mu}_{0}H = \dfrac{c}{\sqrt{{ε}_{r}}} \times \sqrt{{\mu}_{r}} \times {\mu}_{0}H ⇒ E = \dfrac{3 \times {10}^{8}}{\sqrt{6 . 44}} \times \sqrt{1 . 61} \times 4\pi \times {10}^{- 7} \times 4 . 5 \times {10}^{- 2} = 8 . 48V{m}^{- 1}$