A light wave of frequency 5 x 10\(^{14}\)Hz moves through water which has a refractive index of \(\frac{4}{3}\). Calculate the wavelength in water if the velocity of light in air is 3 x 10\(^8\)ms\(^{-1}\)
-
4.5 x 10-7m
- 6.0 x 10-7m
- 1.7 x 106m
- 2.2 x 106m
The correct answer is: A
Explanation
Speed of light in a medium is given by: v = \(\frac{\text{c}}{\text{n}}\)
\(\frac{4}{3}\) = \(\frac{3 \times 10^8}{v}\)
v = 2.25 x 10\(^8\)ms\(^{-1}\)
\(\lambda\) = \(\frac{V}{F}\)
= \(\frac{2.25 \times 10^8}{5 \times 10^{14}}\)
\(\lambda\) = 0.45 x 10\(^{-6}\)m = 4.5×10\(^{−7}\) m