Week 2 Sun and Light Flashcards
why do bodies radiate heat
molecules/atom internally vibrate. These vibrations emit energy
what are Kirchoff’s 3 laws relating to spectrums
1 A hot solid, liquid, gas at high pressure has a continuous spectrum
2 A hot gas at low pressure will produce emission lines
3 A cold gas at low pressure in front of a hot continuum causes absorption lines
what is a blackbody spectrum
spectrum produced by an isothermal opaque and non-reflecting object
what 3 observations can be made from a blackbody graph
1 Total intensity decreases with decreasing temperature
2 Peak shifts to longer wavelength with decreasing temperature
3 Classical theory is wrong
What are the two laws observed during a blackbody experiment
Stefan’s Law: P = σT^4
Wien’s displacement law: λpeak = b/T
what did Planck suggest to account for blackbody’s observed spectrum
If the vibrations did not continuously radiate energy and instead release/gain energy in chunks called quanta of size hf
what is the best blackbody in the known universe
primordial universe
what is the Tyndall Effect
Light passes through a clear fluid holding small particles in suspension the shorter blue wavelengths are scattered more than the longer red ones
what is Rayleigh scattering
scattering of light off of the molecule in the air
why dont we see the shorter wavelength light like violet (2 reasons)
1 These wavelengths are often absorbed higher up in the atmosphere
2 Our eyes are less sensitive to these wavelengths
what causes Mie scattering
particles are larger than 10% of the wavelength of the incident radiation
what are the 3 ways that Mie scattering differs from Rayleigh scattering
Independent of wavelength
Larger in forward direction than reverse
the greater the particle size the greater the scattering
