Question

An electromagnetic wave of v = 3MHz passes from vacuum into dielectric medium with $ϵ=4.0{ϵ}_0.$ Then:

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

Answer 1

The correct option is D

wavelength is halved but frequency remains same.

C = $\frac{1}{\sqrt{\mu ϵ}}$
here; $ϵ=\mu {ϵ}_0$
hence; the speed is halved. Since, the frequency depends on the source and C = f $\lambda$; wavelength will be halved.