ASTR 114 Lecture Notes - Lecture 6: Electromagnetic Spectrum, Electromagnetic Radiation, Photon
Document Summary
We can measure the flow of energy in light in units of watts: 1 watt = 1 joule/sec. There are many different colors of light; white light is the combination of every color. Absorption: opaque (non-transparent) objects absorb light. Reflection/scattering: a mirror reflects light in a particular direction. Interactions between light and matter determine the appearance of everything around us. Why is a rose red: the rose absorbs red light, the rose transmits red light, the rose emits red light, the rose reflects red light. The rose absorbs every other color in the light spectrum, but reflects red light. Light can act either like a wave or like a particle. A wave is a pattern of motion that can carry energy without carrying matter along with it. Wavelength is the distance between two wave peaks (m). Frequency is the number of times per second that a wave vibrates up and down (ghz).