Intro – Radiation and Temperature

Radiative Energy

Energy transferred through electromagnetic waves

Radiative Energy: Properties

No medium required, travels at speed of light

Speed of Light

3 × 10^8 m/s

Electromagnetic Waves

waves that carry radiant energy

Electromagnetic Waves: Wavelength

Distance between 2 wave crests um

Electromagnetic Waves: Frequency (v)

number of wave crests passing a fixed point per second

Electromagnetic Waves: Speed of Light (C)

c = wavelength x frequency

Electromagnetic Waves: Energy

Inversely proportional to wavelength, proportional to frequency

Stefan-Boltzman Law

All objects above absolute 0 must emit radiation

Stefan-Boltzman Law: Formula

constant * temperature^4

Weins Displacement Law

Wavelength is inversely proportional to Temperature

Kirchoffs Law

An object efficiency of emission=absorption

Wavelength: Visible Light

0.4 um (violet) - 0.7 um (red)

Wavelength: Ultraviolet

less than 0.4 um

Wavelength: Infrared

greater than 0.7 um

Wavelength: Earth

Infrared, usually around 10 um

Wavelength: Sun

Emits 44% of its radiation in the visible spectrum