Answer :
Answer:
nr = 1.1994
Explanation:
Critical is the angle at which if increased beyond will cause total internal reflection and total internal reflection only occurs when light is traveling from denser medium to a less dense medium
The formula for critical angle
sin C = nr /ni where ni is the refractive index of the glass and nr is the refractive index of the certain alcohol and C is the critical angle = 47°, ni = 1.64
substitute the values into the expression
ni sin C = nr
1.64 × sin 47
nr = 1.1994