Question

An electromagnetic wave of frequency `v=3.0 MHz` passes from vacuum into a dielectric medium with permittivity `epsilon=4.0`. Then
A. Wavelength is double and frequency become half
B. Wavelength is double and frequency becomes half
C. Wavelength is halved and frequency remains unchanged
D. wavelengthand frequency remain unchanged

Answer 1

Correct Answer - c
Refrance index `=sqrt((mu)/(mu_(0)epsilon_(0))`
Here `mu` is not specified so we can consider `mu=mu_(0)` then refeactive index `=sqrt((epsilon)/(epsilon_(0)))=2`
Hence, speed and wavelength of wave become half and frequency remain unchanged.