Chapter 5 Flashcards
Olaus Romer
Danish astronomer who observed variations in the eclipse time of Jupiter’s moons depending on Earth’s distance from Jupiter in 1676
measuring the speed of light
Armand-Hippolyte Fizeau and Jean Foucac measured the speed of light in 1850 using their rotating mirror device.
wavelength of maximum emission
the wavelength at which a blackbody is radiating most intensely
blackbody
absorbs all radiation which falls on it such that all the light it emits is directly the result of its temperature
visible light
the wavelengths most intense in the sun’s radiation which humans have evolved to see
Wien’s law
relates the temperature of a Blackbody to it’s wavelength of maximum emission
Stefan-Boltzman Law
shows that the amount of energy emitted by a black body is proportional to its temperature to the 4th power
watt
1 joule per second
energy flux
the amount of energy emitted from a square meter of an object’s surface per second
Kirchoff’s laws
Law 1: blackbody’s produce a continuous spectrum
Law 2: hot, transparent gas produces an emission line spectrum
Law 3: cold, transparent gas produces an absorption spectrum
If the gas is hotter than its surroundings, it will emit a spectrum; if it is cooler, it will absorb a spectrum
relationship between absorption and emission lines
are the same for a given element/compound
Helium
first detected in the spectrum of the sun
named after Helios
Rayleigh Scattering
shorter wavelengths of light are more effectively scattered by the atmosphere – blue light is more scattered than red so the sky looks blue; in the evening the light has to go through more atmosphere so more of the blue is scattered and the light looks red/yellow
Balmer Series
the spectral lines visible from Hydrogen in the visible and ultraviolet; describe the electron transitions from n=2
described by Johann Jakob Balmer
Lyman and Paschen series
Lyman: H transitions from n=1 (ultraviolet)
Paschen: H transitions from n=3 (infared)
