ASTR 103 Lecture Notes - Lecture 5: Angular Distance, Parabolic Reflector, Light Pollution
16 Oct 2018
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Light is an electromagnetic wave: light is also referred to as electromagnetic radiation, wavelength: units of length (meters, frequency: units of times per second (1/s or hz) Wavelength and frequency: longer wavelength lower frequency, shorter wavelength higher frequency, wavelength x frequency = speed of light = constant. Particles of light: particles of light are called photons, each photon has a wavelength and a frequency, the energy of a photon depends on its frequency. X rays, and gamma rays: visible light comes in many colors that combine to form white light. Atomic terminology: atomic number: number of protons, atomic mass number: number of protons + neutrons, molecules: consist of two or more atoms. Isotopes: same number of protons, but different number of neutrons. )n astronomy, we use the word (cid:498)spectrum(cid:499) to refer to a plot that has : wavelength (or frequency) in the x-axis, intensity of light (energy per time per area) in the y-axis.
