PHYS 190 Lecture Notes - Lecture 10: Emission Spectrum, Spectroscopy, Redshift
9 Feb 2018
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Cooler objects - redder colours, less intense light (cid:3247)peak(cid:3248) wavelength 1 over temperature. Opaque - all light falling on object gets absorbed. Object absorbing all radiation not all black. Blackbody spectrum has characteristic form that is same for all opaque objects & Blackbody necessarily radiates depends only on object"s temperature. Peak wavelength gets smaller as temperature gets higher. Very rapid change in intensity w/ temperature, while peak wavelength changes more slowly. Though intensity drops rapidly away from peak wavelength. A solid, liquid, or dense gas excited to emit light will radiate at all wavelengths & thus produce continuous spectrum. A low-density gas excited to emit light will do so at specific wavelengths & thus produce an emission spectrum. Each element radiates/absorbs at unique set of wavelengths. If light comprising continuous spectrum passes through a cool, low-density gas, the result will be an absorption spectrum. Blueshift - wavelength shifted to shorter wavelengths.
