(a) A tank containing methanol has walls 2.50cm thick made of glass of refractive index 1.550. Light from the outside air strikes the glass at a 413o angle wills the normal to the glass. Find the angle the light makes will the normal in the methanol.
(b) The tank is emptied and refilled will an unknown liquid. If light incident at the same angle as in part (a) enters the liquid in the tank at an angle of 20.2o from the normal what is the refractive index of the unknown liquid?