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: 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
