Snell's Law states: [math] \large \frac {sin\; \theta_1}{sin\; \theta_2} = \frac {v_1}{v_2} =\frac {n_1}{n_2} [/math].[br]Where v is the velocity in a medium such as air or water, n is the refractive index of the medium, and \theta; is the angle of refraction.