Stars as Black Bodies Flashcards
What is a black body?
A perfect absorber and emitter
A body that absorbs and emits all wavelengths of EM radiation.
Objects emit electromagnetic radiation due to what?
Their temperature
What radiation is everyday temperature?
Infrared (which we can’t see)
Why do things glow if we heat them up?
They emit a different radiation
In what way does a pure black surface emit radiation?
strongly and well defined
The graph of intensity against wavelength varies with what?
TEMPERATURE
What do stars black body radiation produce?
Their continuous spectrum
What does the peak in a black body curve give?
Temperature
The power output is what?
The luminosity
Total energy it emits per second
What is power output related to?
Temperature and surface area
P = σ = A = T = What is each one? What is it measured in?
Power output in watts
Stefan’s Constant
Surface area in meters squared
Temperature in Kelvin
What law does intensity obey?
Inverse square law
Whats the equation for inverse square law?
I = P / 4πd²
