Question

An electromagnetic wave of frequency $v=3.0MHz$ passes from vacuum into a dielectric medium with permitivity $\epsilon =\mathrm{4.0.}$ Then

• A. wavelength is doubled and the frequency remains unchanged
• B. wavelength is doubled and frequency becomes half
• C. wavelength is halved and frequency remains unchanged
• D. wavelength and frequency both remain unchanged.

Answer 1

Answer: (C)

During propagation of a wave from one medium to another, frequency remains constant and wavelength changes
$\mu =\sqrt{\frac{\epsilon }{{\epsilon }_0}}=\sqrt{4}=2$
Since $\mu \propto \frac{1}{\lambda }$