BRAINCAKELuminosity and Intensity
Two different quantities describe how bright a star is, and it is important not to mix them up.
Luminosity (L) is the total power output of a star as electromagnetic radiation, measured in watts (W). It is a property of the star itself and does not depend on where it is observed from. The Sun's luminosity is about 3.9 × 1026 W.
Intensity (I), also called radiation flux, is the power received per unit area at right angles to the direction of the radiation, measured in W m−2:
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Space
- Black-Body Radiation
- Stefan-Boltzmann Law
- Wien's Law
- The Inverse Square Law for Intensity
- Estimating Stellar Radius and Temperature
- The Hertzsprung-Russell Diagram
- Formation of a Star
- Life Cycle of a Star
All 18 lessons in Space · All Edexcel A-level Physics topics