Last Edited By Krjb Donovan
Last Updated: Mar 11, 2014 07:56 PM GMT

## Question

What are ways in which the thermal radiation spectrum of an 8000 k star would differ from a 4000k star.

Hi Lauren, I generally don't do homework, but look up Stefan-Boltzmann Law

http://en.wikipedia.org/wiki/Stefan-Boltzmann_law

and Wien's Law.

The former tells you that the total output power increases as the 4th power of the K (absolute temperature)and the latter tells you that the greatest emitted wavelength of light becomes shorter at the higher temperature, moving it from the infrared for say a cool 4000 K star to the Ultraviolet peak wavelength for an 8000 K star. So just Google both of those laws, and I'll let you fill in the actual arithmetic numbers. (OH, BTW, absolute, or Kelvin temperature is a capital K, not lower case k.) Hope this helps, Clear Skies, Tom Whiting Erie, PA

FOLLOW UP: Lower case k stands for 1000 from the derivation of Kilo.... so it's used in money, for instance 100 grand is written as 100k. Capital K, in addition to degrees Kelvin or absolute, has about 20 + other meanings, in addition to the element Potassium, see http://www.economicexpert.com/2a/Character:K.htm Just thought you'd like to know some more trivia. Clear Skies, Tom