A glass plate whose index of refraction is 1.66 is immersed in a liquid.The surface of the glass is inclined at an angle of 44° with the vertical.A horizontal ray in the glass is incident on the interface.When the liquid is a certain alcohol,the incident ray arrives at the interface at the critical angle.The index of refraction of the alcohol is closest to:

Question

Quizplus · Accepted Answer

The critical angle is the angle of incidence at which the refracted ray is parallel to the interface. For a glass-liquid interface, the critical angle is given by:sin(critical angle) = n2/n1where n1 is the index of refraction of the glass and n2 is the index of refraction of the liquid.In this case, n1 = 1.66 and the critical angle is 44°. Therefore, sin(44°) = n2/1.66, which gives n2 = 1.15.

A Glass Plate Whose Index of Refraction Is 1