Let's tackle subtraction first. Subtraction in hexadecimal works similar to subtraction in decimal. Let's do a pair of decimal problems and see if we can parallel the solution method in hex. Suppose we want to subtract 1586 - 243 (in decimal).
Refraction of Light Rays. the bending or deflection of light rays as they pass through the various media of the eye that include the conjuctiva, cornea, aqueous humor, lens, and vitreous body.
When light waves pass through a material, they change speeds and bend. This is known as refraction. As light waves pass through a transparent material like glass, water, or plastic, they slow down and they'll bend toward a line drawn perpendicular to the surface of the material, known as the normal line.