Question

Ray Optics 2 Problem Statement 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? Visual Representation • Draw a ray diagram • Draw a line normal to the boundary • Show the ray bending in the correct direction Label angles of incidence and refraction measured from the normal . Mathematical Representation • Start with Snell's law and/or the law of reflection Substitute in the known values • Solve for the desired unknown • Check units and assess if your answer is reasonable

Answer 1

The solution is given below.

Visual vertical Glass plate Representation prosmalto Erlast plate ng ) refracted ray x 142 لی alcohol (na) -7 incident say i incident angle rangle of refraction 90° X angle between vertical and norma na y refractive index of alcohol Mathematical ng → refreutive index of glass = 1.56 Representation From above figerse i + x = 90°- x + 42° i=42° 2 From Snelts low a sini ng si sin r oro, sin 42° na = 1.56 sin 90° 1.56X1 na 2-33 sin 42° Answer! index of refraction of alcohol = 2.33

Refractive index has no unit.

For total internal reflection to occur light must incident from a media with higher refractive index (here alcohol ,2.33) to a medium with lower refractive index(here glass , 1.56)

Thank you.