Question

A plane electromagnetic wave

$Ez=100cos(6\times {10}^{8}t+4x)V/m$ propagates in a medium of refractive index

• A. 1.5
• B. 2.0
• C. 2.4
• D. 4.0

Answer 1

The correct option is B

2.0

$E=E_{0}cos(\omega t+kx)$

$\omega =6\times {10}^8,k=4$

$V=\frac{\omega }{k}=\frac{6\times {10}^8}{4}$

$=\frac{3\times {10}^8}{2}m/s$

$\mu =\frac{c}{V}=2$