Section IX - exam 3

Maxwell’s equations

Equations that describe how electric fields and magnetic fields interact and propagate through space.

Magnetic monopoles

Hypothetical particles proposed to exist as isolated magnetic charges, differing from conventional magnets.

Self propagate

The ability of a wave to maintain its shape while traveling at a constant speed in a medium without external influence.

Speed of light (c)

The constant speed at which light travels in a vacuum.

Photon

A quantum of electromagnetic radiation, specifically a particle of light that carries energy and has no mass.

Photoelectric effect

The phenomenon where a photon knocks an electron off a metal atom, producing an electric current.

Alpha particles

Positively charged particles that are identified as helium nuclei.

Beta particles

Negatively charged particles that are identified as simple electrons.

Gamma particles

High energy photons with no charge, representing the highest energy form of electromagnetic radiation.

E/M spectrum

The continuum defined as the intensity of an electromagnetic wave as a function of wavelength, frequency, or energy.

Gamma rays

The highest energy, highest frequency, and shortest wavelengths of electromagnetic radiation.

X-rays

Electromagnetic radiation with wavelengths between 0.01 nm and 10 nm, emitted by low-energy nuclear reactions.

Ultraviolet (UV)

Electromagnetic radiation with wavelengths between 10 nm and 400 nm, emitted by electron transitions in atoms.

Visible (visual)

Electromagnetic radiation with wavelengths between 400 nm and 700 nm that is perceivable by the human eye.

Infrared (IR)

Electromagnetic radiation with wavelengths between 700 nm and 1 mm, often emitted by thermal processes.

Microwaves

Electromagnetic radiation with wavelengths between 1 mm and 10 cm, emitted by electronic devices.

Radio waves

Electromagnetic radiation with wavelengths greater than 10 cm, having the lowest energy and frequency.

Kirchhoff’s law #1

A luminous opaque object emits light at all wavelengths, producing a continuous spectrum.

Kirchhoff’s law #2

A rarefied luminous gas emits light showing an emission-line spectrum against a dark background.

Kirchhoff’s law #3

An absorption-line spectrum appears when white light passes through a lower-density gas.

Ideal radiator

A hypothetical body that completely absorbs all radiation and reradiates it when equilibrium temperature is reached.

Energy flux (F)

The energy emitted per unit area each second, proportional to the fourth power of temperature.

Luminosity (L)

The total amount of energy emitted by an object per unit time, related to surface area and temperature.

Wien’s displacement law

The principle stating that the peak wavelength of radiation from a blackbody is inversely proportional to its temperature.

Planck curves

Graphs illustrating the distribution of electromagnetic radiation emitted by a blackbody at a given temperature.

Spectral lines

Distinct dark or bright lines in a spectrum that correspond to specific wavelengths absorbed or emitted by elements.

Spectral analysis

The method of breaking light into colors to analyze spectra and identify elemental compositions.

Spectrograph

A device that separates white light into its component colors to display spectral lines.

Quantum mechanics

Branch of modern physics that describes the allowed orbits of electrons around atomic nuclei.