Answer:
The reflectivity at the boundary of the two grains is
×
Step-by-step explanation:
Given :
Refractive index of one grains (
) = 1.553
Refractive index of second grains (
) = 1.544
According to the fresnel equation,
∴ general equation of refraction ( reflectivity ) 
where
= incident angle,
= transmitted angle
but for normal incidence
°
so our equation become,
⇒ 


×
Therefor reflectivity at the boundary is given by
×
.