Units 24-28 Flashcards
Energy Levels
the orbitals electrons move in
-quantized energy levels
Bohr Model of the Atom
describes the electron as orbiting at a set of discrete radii
Energy of Hydrogen eq
En=(-2.180 x 10^-18 J)/n^2
Emission line spectrum
the different light emission from a hot gas, containing different x
unique to elements
Balmer Lines
transitions between n=2 energy levels and higher levels
Continuous spectrum
atoms must be packed so that electron energy levels are altered so each atom can interact with photons of different energies therefore allowing photons of all lambda to be emitted
emission line spectrum
isolated atoms and molecules emit light only at certain wavelengths
produced by hot low density gas
absorption line spectrum
produced when light from a hot dense body passes through cooler gas. All colors are present but light at certain wavelengths is missing
radial velocity
an object moving directly away from us
Doppler formula
Vr=( delta lambda/lambda) x c
Redshifts
longer wavelength
Blueshifts
Shorter wavelength
Doppler Broadening
if atoms in a gas are moving, spectral lines will be spread over a wider range of wavelengths
Rest frame
A coordinate system tied to the solar system’s position and motion in which it appears we are at rest
Galilean relativity
how motions add to and subtract from one another
motions depend on rest frame
Aether
scientists believed this substance existed, through which light waves always traveled at the same speed
Lorentz factor
hypothesizes that an object’s length shortens in the direction in which it is moving by a factor equal to
gamma= 1/root((1-v^2)/c^2)
Twin paradox
it seems as though the astronaut twin and the earth twin should each age slowly from the other’s point of view
astronaut would actually be aging slower
free fall
when no forces resist motion in a gravitational field
principle of equivalence
idea that gravity has the same effect on an object as being in an accelerating frame of reference
-an observer in freefall measures time normally so stationary clocks on the tower must be running slower
Gravitational lensing
deflections can sometimes focus and brighten the light from a backgrounded object
allows astronomers to detect objects that may not be visible
curvature of space
produced by mass and energy
gravitational time dilation
tells us how much slower clocks run in a gravitational field based on Vesc
Gravitational waves
when one object orbits another the motion of the two objects generate gravitational waves
