Step-by-step explanation:
Through Snell's Law, we can solve this.
The formula is:
n1 * sin(theta1) = n2 * sin(theta2)
n1 = flint = 1.66
n2 = water = 1.33
theta1 = 26.0°
theta2 = angle of refraction
Substituting these values in the formula,
1.66 * sin(26) = 1.33 * sin(x)
[1.66 *sin(26)] ÷ 1.33 = sin( x )
0.5471 = sin(x)
arcsin(0.5471) = x
33.17 = x
Therefore, the angle of refraction is 33.17°
b.) Using the same formula, we have:
1.66 * sin(x) = 1.33 * sin(90)
sin(x) = [1.33 * sin(90)] ÷ 1.66
sin(x) = 0.8012
x = arcsin(0.8012)
x = 53.2453°
Therefore, the light needs to have an angle of incident of 53.2453° in order to have a 90° angle of refraction.