Question

An electromagnetic wave of frequency v = 3.0MHz passes from vacuum into a dielectric medium with permitivity s = 4.0 ε₀ . Then

(a) Wavelength is doubled and frequency becomes half 

(b) Wavelength is doubled and the frequency remains unchanged. 

(c) Wavelength and frequency both remain unchanged 

(d) Wavelength is halved and frequency remains unchanged.

Answer 1

(d) Wavelength is halved and frequency remain unchanged.

When a wave goes from one medium to another, its frequency remains unchanged. According to equation C = \(\frac{1}{\sqrt{με}}\), the speed is halved. Therefore, the wavelength is also halved.