Question

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 44º 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: O A. 1.13 OB. 1.17 O C. 1.15 O D. 1.11

Answer 1

Answer:

C. 1.15

Explanation:

The formula for the critical angle is:

${sin\theta_{critical}}=\frac {n_r}{n_i}$

Where,  

${\theta_{critical}}$ is the critical angle

$n_r$ is the refractive index of the refractive medium.  ( Alcohol , ? )

$n_i$ is the refractive index of the incident medium.  ( Glass, 1.66 )

Critical angle =  44º

Applying in the formula as:

${sin\theta_{critical}}=\frac {1}{1.523}$

${sin\ 44^0}=\frac {n_r}{1.66}$

${n_r}=1.15$