Answer:
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
[tex]R = [\frac{n2 - n1}{n2 + n1} ]^{2}[/tex]
since the incidence is normal where R, is the index of relativity
[tex]R = [\frac{1.779 - 1.757}{1.779 + 1.757} ]^{2}[/tex]
R = 3.87 x 10⁻⁵