Calculate the critical angle between diamond (n = 2.42) and quartz (n = 1.46)?

23°
37°
52°
60°

37°

Explanation:

Total internal reflection is a phenomenon that occurs when a ray of light is moving from a medium with higher index of refraction to a medium with lower index of refraction; in this case, there exist a value of the angle of incidence (called critical angle, ) above which no refraction occurs, and all the light is reflected back into the original medium.

The value of the critical angle between two mediums is given by the formula:

where

is the index of refraction of the 1st medium

is the index of refraction of the 2nd medium

In order to have total internal reflection, it must be .

In this problem:

is the index of refraction of diamond

is the index of refraction of quartz

Substituting, we find the value of the critical angle:

96.77 amp

explanation:

rl = 250/100 = 2.5 ohms.

egl = 250 + (100 × 0.1) + 2 = 262 v.

at 700 r.p.m., eg2 = 262 × 700/1000 = 183.4 v.

if ia is the new current, then eg2 - 2 - (ia × 0.1) = 2.5 ia

which means this will give ia = 96.77 amp.