The velocities of light in air and glass are 3.0 x 10\(^8\)ms\(^{-1}\) and 2.0 x 10\(^8\)ms\(^{-1}\) respectively. If the angle of refraction is 30º, the sine of the angle of incidence is?
0.33
0.50
0.67
0.75
Correct answer is D
\(\frac{\text {sin i}}{\text {sin r}}\) = \(\frac{\text {velocity in air}}{\text {velocity in glass}}\)
\(\frac{\text {sin i}}{\text {sin 30}}\) = \(\frac{3 \times 10^{8}}{2 \times 10^{8}}\)
Sin i = \(\frac{3}{4}\) = 0.75