The speed of light in air is \(3 \times 10^{8} ms ^{-1}\). If the refractive index of light from air to water is \(4 / 3\), calculate the speed of light in water.
A. \(2.25 \times 10^{8} ms ^{-2}\) B. \(2.25 \times 10^{8} ms ^{-1}\) C. \(4.00 \times 10^{8} ms ^{-1}\) D. \(4.33 \times 10^{8} ms ^{-1}\)
Correct Answer: B
Explanation
$$ { }_{\circ} \eta_{w}=\frac{\text { speed of light in air }}{\text { speed in water }} \text {; } $$ \(\frac{4}{3}=\frac{3 \times 10^{8}}{\text { speed in water }}\) speed in water \(=\frac{3 \times 10^{8} \times 3}{4}\)
