Key Terms
Quantized
A physical quantity that can only take certain discrete values; NOT continuous. Continuous: the opposite — can take any
Examples of quantized things
Atoms, electron charge, energy levels in oscillators. Examples of non-quantized (continuous) things: position of a car o
Quantum mechanics
The branch of physics dealing with small (submicroscopic) objects and the quantization of entities like energy and angul
Correspondence principle
In the classical limit (large, slow-moving objects), quantum mechanics produces results indistinguishable from classical
Blackbody
An ideal radiator with emissivity = 1 at all wavelengths; absorbs and emits all EM radiation perfectly. Appears jet blac
Blackbody radiation
The EM radiation emitted by a blackbody.
Atomic spectra
The discrete EM emissions from individual atoms and molecules when electrons transition between energy levels.
Line spectrum
Only certain discrete wavelengths (and therefore frequencies) are emitted — not a continuous range. This is direct evide
Photoelectric effect
When EM radiation strikes a material and ejects electrons from it.
Conversion
1 eV = 1.602 x 10^-19 J
EXAMPLE WALKTHROUGH
420-nm violet light on calcium (BE = 2.71 eV)
Convert
4.74e-19 / 1.602e-19 = 2.96 eV
Bremsstrahlung
"braking radiation." Produced when electrons decelerate in anode material. Creates a smooth continuous x-ray spectrum.
Characteristic x-rays
Sharp peaks in the x-ray spectrum; unique to the anode material; produced by atomic excitations specific to that element
Cathode ray tube (CRT)
Electrons from a hot cathode filament are accelerated through high voltage. When they strike the anode, they produce x-r