micro meter = millionth of a meter micro meter = m visible light 0.4 m to 0.7 m

• 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