Electromagnetic radiation

• electromagnetic radiation (EMR) (or electromagnetic wave (EMW))

• “sources and types”:todo

  • accelerating charged particlestodo
  • thermal radiation
  • atomic electron transition
    • Planck relation
  • Cyclotron radiation
  • Cherenkov radiation
  • nuclear fusion
  • see also: methods of generation of visible light

• bremsstrahlung (קרינת בלימה)

  • $K=eV$ is the kinetic energy of the accelerated electron

Energy

• energy density of an electromagnetic wave
  • $u=u_E+u_B=\frac{1}{2}{ϵ}_0{E}^2+\frac{1}{2{\mu }_0}{B}^2={ϵ}_0{E}^2$
• average intensity
  • $I_{\text{avg}}=\frac{1}{2}c{\epsilon }_0{E}_0^2$
• photon energy
• radiant energy

Thermal radiation

• thermal radiation (קרינה תרמית (or קרינת חום))
  • “electromagnetic radiation emitted by the thermal motion of particles in matter” (Wikipedia)

Black-body radiation

• black-body radiation
  • ”thermal electromagnetic radiation emitted from a body in thermodynamic equilibrium with its environment” (Wikipedia)
  • “The radiation emitted by a black body in thermal equilibrium with its environment” (Wikipedia)
  • black body (or blackbody)
    • “an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence” (Wikipedia)
  • examples: cosmic background radiation
• Wien’s displacement law
  • ${\lambda }_{\text{max}}=\frac{b}{T}$
  • ${\lambda }_{\text{max}}$ is the wavelength at which
  • $b$ is the Wien’s displacement constant
• Stefan–Boltzmann law
  • $E=\sigma T^4$ is the radiant exitance
  • $T$ is the absolute temperature of the black body
  • $\sigma$ is the Stefan–Boltzmann constant
• Planck’s law

Electromagnetic spectrum

• electromagnetic spectrum

  • gemma ray
  • X-ray
  • ultraviolet radiation (UV) (or ultraviolet light)
  • visible light
  • infrared (IR) (or infrared light)
  • microwave
  • radio wave

• optical radiation

Visible light

• methods of generation
  • incandescent light bulb (or incandescent lamp) (נורת להט, נורת ליבון)
  • luminescence (נְהוֹרָנוּת) (or cold light)
    • photoluminescence (נהורנות אורית, נהורנות אור)
      • fluorescent
    • LED
  • combustion
  • electric arc (קשת חשמלית)
  • gas discharge lamp – “sending an electric discharge through an ionized gas, a plasma” (Wikipedia)
    • neon lighting
    • sodium-vapor lamp
    • high-intensity discharge (HID)

Radiometry

• radiometric quantities:

  • radiant energy (אנרגיית קרינה) is the energy of electromagnetic radiation
  • radiant exposure (or fluence)
    • the radiant energy received by a surface per unit area
    • SI unit: $J/{\mathrm{m}}^2$
  • spectral radiance (or specific intensity)
  • radiant flux (or radiant power)
    • SI unit: $\mathrm{W}$
  • irradiance
    • SI unit: $W/{\mathrm{m}}^2$
  • radiant exitance (or radiant emittance)
    • SI unit: $W/{\mathrm{m}}^2$
    • see: Stefan–Boltzmann law
  • radiosity
    • SI unit: $W/{\mathrm{m}}^2$
  • see also: https://en.wikipedia.org/wiki/Radiometry#Radiometric_quantities

• beam energy

• kerma

• linear energy transfer

• see also:

  • radiation dosimetry
  • measurement of radioactive decay
  • photometry