The speed of light in air is 3 x 108ms-1. If the refractive index of light from air-to-water is (frac{4}{3}), then which of the following is the correct value of the speed of light in water?
-
A.
4 x 108ms-1 -
B.
2.25 x 108ms-1 -
C.
(frac{4}{9}) x 108ms-1 -
D.
2.25 x 102ms-1 -
E.
4.33 x 108ms-1
Correct Answer: Option B
Explanation
Air to water = (frac{text{speed in air}}{text{speed in water}})
(frac{4}{3}) = (frac{3 times 10^8}{V})
4V = 3(3 x 108)
V = (frac{3(3 times 10^8)}{4})
V = 2.25 x 108ms-1