BIOL 4041 Lecture Notes - Lecture 19: Total Internal Reflection, Electromagnetic Spectrum, Image Resolution
Document Summary
Refraction allows an image to be formed. Diffraction limits our ability to see well (limits image resolution) Refraction: light is an electromagnetic wave: external energy accelerates electron vibrations in atoms, vibrations generate electric eld, electric eld induces magnetic eld, electric and magnetic oscillations mutually induce each other; do not gain or lose energy. Light is directional and travels at different speeds in different media: interacts with matter in: re ection, refraction, and diffraction. Light needs no medium for propagation and operates best in a complete vacuum. Can differentiate different light wavelengths as color (only a small part of the electromagnetic spectrum) When light moves from a faster medium to a slow medium, the light wave bends toward normal . Fermat"s principle: path taken by light will be that which takes the least amount of time. Ants follow fermat"s principle: the fastest route to food uses diffraction and follow the same pathway that light would.
