Question

An electromagnetic wave in transparent medium is given by $E_x(y,t)=E_{ox}sin2\pi$ $[\frac{y}{5\times {10}^{-7}}-3\times {10}^{14}t]$ in SI units. Then what is the refractive index of the medium?

Answer 1

$\omega =2\pi \times 3\times {10}^{14}$

$k=\frac{2\pi }{5\times {10}^{-7}}$

$v=\frac{\omega }{k}=3\times {10}^{14}\times 5\times {10}^{-7}$

$⟹v=1.5\times {10}^{8}m/s$

Refractive index $\mu =\frac{c}{v}=\frac{3\times {10}^8}{1.5\times {10}^8}$

$⟹\mu =2$