Cos ϕ. This light must vacation farther than the axial light to succeed in a screen, then it strikes the screen at another angle ϕ. The net final result is that the oblique illumination over the display is lesser in comparison to the axial illumination with the element cos4 ϕ. https://best-bluetooth-speaker78665.daneblogger.com/29358330/free-sound-effects-an-overview