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\(^{-1}\)
A
4.5 x 10-7m
B
6.0 x 10-7m
C
1.7 x 106m
D
2.2 x 106m
Verified Correct Answer: A.
Physical Principles & Numerical Solution
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\times10\(^{−7}\) m
Source: Myschool Past Questions Archive (Record #28250)