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
Verified Correct Answer: B.
Physical Principles & Numerical Solution
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
Source: Myschool Past Questions Archive (Record #29223)