Electromagnetic spectrum
Spectrum Very broad Wavelengths from 10-3 to 1013 nm Only small portion is visible to humans 400nm (violet) to 700nm (red) ROYGBIV
Wave Characteristics Amplitude Vertical distance from the centerline
Wave Characteristics Wavelength (λ) Measured from crest to crest
Wave Characteristics Frequency (v) Cycles (waves) per second
Wave Characteristics Speed of light in a vacuum 3.00 x 108 = c Speed , wavelength and frequency are related c = λv v = frequency λ = wavelenght
Wave Components Two components Electric field Magnetic field They both have the same characteristics (wavelength, frequency, and amplitude) Perpendicular to eachother
Wave Components
How Light Moves Double slit experiment Thomas Young Early 1800’s When light passes through a single slit it forms a cone shape on a plane behind the slit When light passes through two slits the light waves interfere with itself
Wave Components
Wave Components When an object is heated it gives off radiation Over a wide range of the spectrum Energy given off by an object at a certain temperature depends on wavelength Some theories explained the long wave-length dependence Other theories explained the short wave-length dependence
Quantum Theory Old theory was radiant energy was continuous Based on blackbody experiments Planck proposed the energy was actually in packages or bundles Called these packets of the smallest quantity of energy quantum
Quantum Theory The energy of a single quantum is always in whole numbers May seem strange but many of the smallest units we are used to are in whole numbers Soda, eggs…
Quantum Theory Energy of the quantum is dependent on the frequency E = hv E is the energy of a quantum v is the frequency h is Planck’s constant 6.63 x 10-34J·s
Two Equations c = λv E = hv c is a constant 3.00 x 108 m/s h is a constant 6.63 x 10-34 J·s
Electron Energy En = -2.18 x -18 J (1/n2) As electron gets closer to nucleus Has more energy When n=1, at ground state When n>1, excited
E = hv
EM Spectral Lines
EM Spectral lines
EM Spectral lines