The source treats incoming light as traveling from air, index one, into glass. Snell’s equation divides the sine of the incident angle by the chosen glass index. With the default index one point five two and a forty five degree incident angle, the sine becomes approximately zero point four six five. Taking the inverse sine gives about twenty seven point seven degrees inside the glass. The animated ray uses these actual angles. At normal incidence the source’s two polarization reflection formulas agree. The reflection fraction is the square of the index difference divided by the index sum. For index one point five two this is roughly four point two six percent. The display calculates transmission as one hundred minus reflection, giving about ninety five point seven four percent. These are the model’s ideal interface fractions, without absorption or an actual phone construction. The source also displays inverse sine of one divided by glass index: about forty one point one degrees at index one point five two. That critical angle describes light trying to leave denser glass for air. The incoming calculation here remains air to glass; its sine ratio cannot exceed one when glass index is greater than one. Curvature and thickness change the depicted geometry, while this educational model is not a manufacturing or device performance validation.