An electromagnetic wave of frequency `v=3.0 MHz` passes from vacuum into a dielectric medium with permittivity `epsilon=4.0`. Then

Options

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

C

Explanation

Refractive index,`mu=sqrt((epsilon)/(epsilon_(0)))=2`
Speed and wavelength of wave will becomes half the frequency remaining unchanged (frequency of a wave depends on the source as due to refraction, it is assumed that the energy is conserved, hv remains the same)