21.13 The index of refraction of corundum (Al2O3) is anisotropic. Suppose that visible light is passing from one grain to another of different crystal-lographic orientation and at normal incidence to the grain boundary. Calculate the reflectivity at the boundary if the indices of refraction for the two grains are 1.757 and 1.779 in the direction of light propagation.

3.87 x 10⁻⁵

Explanation:

Given parameters

normal incidence

refraction index of grain1, n₁ = 1.757

refraction index of grain2, n₂ = 1.779

to calculate reflectivity index between the two grains of different orientation an at normal incidence, we use the relation

since the incidence is normal where R, is the index of relativity

R = 3.87 x 10⁻⁵

x+2 because it just doubles hon so the pattern can actually tell you the expression.

so for example,

if x=2 then 2+2 is 4

if x=4 then 4+4 is 8

and so on and so forth.

i really hope that this makes sense and you out in a way hon: )