Details Title: Astronomy 161 Description: plantets, light and matter Total Flash Cards: 68 Created: 12/07/2008 13:48:36		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Astronomy Flashcards
Cards in this set: Term Young's "Double Slit" Expirement: Bright Bands Definition where light waves from the two slits reinforce each other Term Young's "Double Slit" Expirement: Dark Bands Definition where light waves from the two slits cancel Term wave length symbol Definition λ Term light travels in... Definition waves Term different colours in light have... Definition different waves lengths Term light travels at a speed of... Definition c= 300,000 km/s Term does light have an infinate amount of speed? Definition no Term is light electromagnetic radiation? Definition yes Term light periodically changes in strengths of what? Definition electric and magnetic fields Term light travels through a vaccuum at what speed? Definition the speed of light Term light doesn't need a ______ to "wave" in Definition "medium" Term the speed of light is a _______ for all light waves Definition constant Term what are the 3 #'s light waves are characterized by and what is the formula? Definition #1-wavelength; λ(size of wave) #2- frequency; f (# of waves/sec) #3- wave speed (c)   c=λ f Term since c is the same for all light waves, longer λ means... Definition smaller frequency Term wavelength and frequency are related how? Definition v=c/λ Term low frequency =   Definition long wave length Term high frequency = Definition short wavelength Term a dense, hot object emits according to... Definition it's temperature (T) Term temperature determines... Definition brightness and colour (λ at which most light is emitted) Term from hot to hottest, what is the colour emitted typically?   Definition hot=red, hotter= redish-orange, hottest=white-yellow Term absolute temperature at high temperatures = Definition atoms + molecules move very rapidly Term absolute temperature at cooler temperatures = Definition atoms + molecules move more slowly Term if temperature is cold enough, all motion... Definition stops Term what does absolute zero correspond to? Definition -273° C Physically unobtainable ultimate lower limit Term black body radiation: Definition absorbe everything, reflect nothing. light coming out depends on temperature only. Term Wien's Law relates... Definition peak wavelength and temperature Term what colour are hotter objects? Definition blue Term what colour are cooler objects? Definition red Term as temperature increases... Definition wavelength decreases     Term the wavelength of maximum emission of a black-body is inversely proportional to it's temperature in Kelvins Definition λ max = 0.0029/ T Term Stefan - Boltzmann's Law: Flux from a black body is proportional to the fourth power of the objects temperature Definition F = σ T 4(th power) Term Hotter objects are ______ at ______wavelengths and ______. Definition (1) brighter (2) all (3) bluer Term photons: Definition particles of light Term photons are a ______ particle that carries energy at the speed __________ Definition (1) massless (2) of light Term photon energy: Definition E=hv or E= h c/λ Term Planicks constant = Definition h Term higher frequencies mean... Definition higher energies Term electromagnetic spectrum: Definition photon energies high to low Term low energy=low frequency= Definition long wavelength Term high energy=high frequency= Definition short wavelength Term particle nature of light explains: Definition photoelectric effect Term photoelectric effect: Definition ultra violet light dislodges electrons out of metal (generates electricity) Term each energy has its own set of unique... Definition spectral lines Term you can tell elements apart by their... Definition spectra Term isotopes show the same _____ , but slightly shifted in ________ Definition (1) lines (2) wavelength Term Kirchoff's Laws: #1 A hot, solid or hot, dense gas produces a ____ #2 A hot, low-density gas produces an__________ #3 A continuous spectrum source viewed through a cooler, low-density gas produces an________ Definition #1- continuous spectrum #2- emission-line spectrum #3- absorbtion-line spectrum Term for a particular gas, the wavelength of a ___________ are the same as a __________. Definition (1) absorption line (2) emission line Term From emission or absorbtion lines in an objects spectrum we can learn 4 things Definition 1) which elements are present and in what proportions 2) which elements are ionized, in whole or a part 3) which molecules are present 4)gas temperature, pressure and density Term an atom is made of what? Definition small dense nucleus containing protons and neutrons surrounded by electrons Term electrons can only orbit... Definition in discrete orbitals Term Each orbital corresponds to a _____ _____ or the orbiting electron. Definition particular energy Term if an electron does not have exactly the right energy... Definition it cannot be in an orbital Term spectral lines are proceded when... Definition an electron jumps from one energy level to another within an atom Term In the Bohr Model, electrons have discrete orbits. This model helped explain what? Definition the emission and absorbtion lines Term Emission Lines Definition more light at specific wavelength Term Emission lines Definition more light at specific wavelengths Term Absorbtion lines Definition less light at specific wavelengths Term Emission lines Definition an electron jumps from a higher to lower energy orbital Term an emission line emits how many photons Definition only 1 with the exact amount of energy difference between orbitals Term emission lines get bigger jumps when they... Definition emit higher energy (bluer) photons Term Absorbtion lines... Definition when an electron absorbs a photon with exactly the energy needed to jump from a lower to a higher orbital Term photons are absorbed only with... Definition the exact excitation energy Term molucules produce... Definition absorbtion bands Term The Doppler Effect Formula: Definition ∆λ/λ = v/c Term If an object is moving towards the observer, its spectrum appears: Definition blue-shifted Term blue-shifted wavelengths of an objects spectral line appear... Definition smaller Term if an object is moving away from the observer, the spectrum appears Definition red-shifted Term red-shifted wavelengths of an objects spectral line appear... Definition larger