### Rutgers University Institute of Marine and Coastal Sciences

#### A blackbody is defined as an object that absorbes all incoming radiation and emmits all energy at full efficiency for all wavelengths. The amount of energy emmitted by a blackbody can be calculated for different wavelengths. The following equation is used to calculate the magnitude of this wavelength dependent radiation. #### A plot of this equation for different temperatures is shown below. The x-axis is wavelength, and the y axis is radiation intensity (B). #### As the temperature increases the magnitude of the peak increases and shifts toward shorter wavelengths. The following equation describes the temperature dependence of the curves: #### Using the above equation the wavelength that yeilds the most radiation can be calculated for a given temperature. While the above equation is based on an ideal blackbody, approximations can be made for other objects. Wein's Displacement Law provides scientists with a means to calculate these peak wavelengths for any known temperature. The following figure illustrates the relative locations of the blackbody peaks for the sun and the earth. ### **Note:The magnitude of the Earth curve has been magnified 500,000 times.

#### -This page has an abundance of pictures to describe the properties of a blackbody 