2: Light
- Page ID
- 30460
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Chapter 2 centers on the nature of light, which is humanity’s primary source of information about the Universe. It discusses the dual nature of light as both a particle and a wave; the relationship between wavelength, frequency, and speed; the wavebands of the electromagnetic spectrum; and continuum and line spectra.
- 2.0: Light Introduction
- Almost everything that we know about the Universe ultimately comes from the light we observe. Looking at the sky on a dark night is a breathtaking experience, and the Universe contains much more than is visible to the naked eye!
- 2.1: The Wave Nature of Light
- You will know that light can act like either a wave or a particle. You will know that all types of light travel at the same speed. You will be able to distinguish between wavelength, frequency, and speed You will be able to perform calculations and understand conceptually the relationship between wavelength, frequency, and speed.
- 2.2: The Particle Nature of Light
- ou will be able to perform calculations and understand conceptually the relationship between energy and frequency.
- 2.3: The Electromagnetic Spectrum
- You will be able to rank the different bandpasses in the EM Spectrum by energy, frequency, and wavelength.
- 2.4: What a Spectrum of Light Can Tell Us About Matter
- You will be able to describe how light can be measured as a function of energy (spectroscopy).
- 2.5: Continuous Spectra - a Planck Spectrum Tells us the Temperature of Objects
- You will know that most light seen in the universe is thermal and can be represented by a Planck spectrum. You will be able to perform calculations and understand conceptually the relationship between temperature and peak wavelength. You will be able to perform calculations and understand conceptually the relationship between flux and temperature.
- 2.6: Lines Spectra- Emission and Absorption Lines
- You will be able to distinguish between emission and absorption lines in a spectrum. You will know how spectral lines are produced. You will be able to calculate the energy/frequency/wavelength of a photon absorbed or emitted by a hydrogen atom.
- 2.7: Determining the Composition of an Unknown Gas
- You will know that chemical elements leave distinct “fingerprints” on the light from astronomical sources.