Lecture 6 Flashcards
waves
amplitude: distance between peak
wavelength: one cycle
interference of waves
check notes
in phase: increases amplitude
out of phase: cancel out
standing waves
oscillates- moves repeatedly from side to side or up to down in time
peaks don’t move around in space
location of any wave can’t be determined
nodes (0), at equilibrium
harmonics
check notes
as the number of oscillation increases, harmonics increase
electromagnetic radiation
transverse waves
oscillating electric and magnetic fields perpendicular to each other and to direction of propagation
c = wavelength x v
wave particle duality
waves don’t explain the photoelectric effect
when light is shone at a metal plate, an e- is emitted
the number of e- emitted depends on a frequency of light (not intensity)
light is discrete, not continuous (like waves)
high frequency = high energy particles
photons
particles of light
one photon with high energy can emit an e-
many photons of low energy, cannot eject an e-
example of mole of photons
check notes
bohr model of an atom
potential energy of an electron is quantised
e- can only be found in specific energy levels
energy increases with distance
e- can move to a higher energy level, energy is needed
photon of specific energy absorbed to do this
photon emitted, e- can return to a lower level
calculating energy of photons
calculated through the gaps of energy levels
equation: check notes
electron transitions
check notes
absorption and emission spectra
white light can be separated by wavelength using a prism
absorption spectrum: photons absorbed
emission spectrum: photons emitted
quantum mechanics
wave particle duality works with:
light, energy, electrons, all little things
de Broglie equation
wavelength = h/mv
electrons
particles
smaller and faster than macroscopic things
wave like nature
