Energy Transfer by Heating - Infrared radiation

Infrared Radiation

• Infrared radiation is part of the electromagnetic spectrum.
• The higher the temerature of an object, the more radiation it emits.
• An object that has a constant temperature, emits radiation across a continuous range of wave lengths.

Black Body Radiation

• Black body radiation absorbs all the radiation that hits it, this makes it the best possible emitter.
• A light, shiny outer surface emits a lot less radiation than a dark, matt surface

The Sun and the Earth

• The sun emits lots of electromagnetic radiation but the eartth blocks the harmful radiation. However it doesn't block infrared radiation or light from the sun.
• The earths temperature depends on absorption of infrared radiation from the sun and the emmission of radiation from the Earth's surfsce and atmosphere.

Key points

• The temperature of an object increases if it ansorbd more radiation than it emits
• The hotter the objest, the more infrared radiation it emits.