The light beam passes from air to water. The angle of refraction is 47 °, the angle of incidence is 74 °

The light beam passes from air to water. The angle of refraction is 47 °, the angle of incidence is 74 °. Determine the speed of light in the water.

It is known from the condition that the light beam passes from air to water. It is also known that the angle of refraction is 47 °, the angle of incidence is 76 °. And we need to determine the speed of light in water.

We’ll start by determining the refractive index of water. To do this, we have to find the ratio of the sine of the angle of incidence to the sine of the angle of refraction.

n = sin 76 ° / sin 47 ° = 0.97 / 0.73 is approximately equal to 1.33.

Otherwise, it is fashionable to find the refractive index like this:

n = c / v;

Substitute values and perform calculations:

n = 3 * 10 ^ 8 / 1.3 = 2.256 * 10 ^ 8 m / s.