• Micro meter = millionth of a meter
Micro meter = m
Visible light 0.4 m to 0.7 m
Radiation Laws
As temperature increases wavelength of maximum radiant intensity, max, increases.Wein’s Displacemnet Law.
max 3000(m K)
TK
Sun
Earth
T=6000 K
T=300 K
Radiation Laws
As temperature increases wavelength of maximum radiant intensity, max, increases.Wein’s Displacemnet Law.
max 3000(m K)
TK
max 3000(m K)
6000K0.5mSun
Earth max 3000(m K)
300K10.0m
Radiation Laws
As temperature increases total radiation output increases. Stefan_Boltzman Radiation Law.
Brightness = Intensity Energy leaving an object each sec per square meter
Intensity T4
As T double Brightness increases by ___??____
As T triples Brightness increases by _______
Radiation Laws
As temperature increases total radiation output increases. Stefan_Boltzman Radiation Law.
Brightness = Intensity Energy leaving an object each sec per square meter
Intensity T4
As T double Brightness increases by 16
As T triples Brightness increases by _____
Intensity T4
Black Body =1.0
The hole acts like a blackbody. All radiant energy is absorbed none is reflected. If the inside of the cavity were to become hot then the hole would glow.
Image modified from:http://www.usatoday.com/weather/tg/wghwrmng/wghwrmng.htm
Surface gets energy only from the sun when there is no atmosphere
No Atmosphere
Solar In IR out
Surface gets solar energy from the sun and infrared energy from the atmosphere when there is an atmosphere.
Image modified from:http://www.usatoday.com/weather/tg/wghwrmng/wghwrmng.htm
With an Atmosphere