An electromagnetic wave of frequency 5.0 x 1014Hz, is incident on the surface of water of refractive index (frac{4}{3}). Taking the speed of the wave in air as 3.0 x 108ms-1, calculate the wavelength of the wave in water.
-
A.
2.2 x 10-6m -
B.
1.7 x 10-7m -
C.
8.0 x 10-7m -
D.
6.0 x 10-7m -
E.
4.5 x 10-7m
Correct Answer: Option E
Explanation
(_an_w = frac{lambda_a}{lambda_w})
(frac{4}{3} = frac{lambda_a}{lambda})
(lambda_w = frac{v}{f})
= (frac{3.0 times 10^8}{5.0 times 10^{14}} = 0.6 times 10^{-6})
(lambda_w = frac{3}{4} lambda_a = frac{3}{4} times 0.6 times 10^{-6})
= 4.5 x 10-7m