A Glass Plate Whose Index of Refraction Is 1

Multiple Choice

A glass plate whose index of refraction is 1.56 is immersed in a liquid.The surface of the glass is inclined at an angle of 42.0° 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.What is the index of refraction of the alcohol?

A) 1.04
B) 1.02
C) 1.00
D) 0.984
E) 1.06