how would i go about solving this problem?

Question

what formula shoud i use?
can you please show me in steps how to do this, thanks a lot:

The critical angle of refraction for calcite is 68.4degrees when it forms a boundary with water. Use this information to determine the speed of light in calcite.

thanks!

Answer 1

Use Snell's law. Find the index of refraction in calcite, and from that, the speed of light. Notice at the critical angle, the angle of the refracted ray is 90 deg.