Radio waves travel in air at 3.0 x 108ms-1. If the waves enter water of refractive index (frac{4}{3}), calculate the speed of radio waves in water
-
A.
4.33 x 108ms-1 -
B.
4.00 x 108ms-1 -
C.
2.25 x 108ms-1 -
D.
1.33 x 108ms-1
Correct Answer: Option C
Explanation
(_an_w = frac{4}{3} = frac{text{speed of light in air}}{text{speed of light in water}})
(frac{4}{3} = frac{3 times 10^8}{x})
x = (frac{9 times 10^4}{4})
= 2.25 x 108m/s