The total power of radiation emitted by a star is called:

The correct answer is Luminosity. Luminosity is the total amount of electromagnetic radiation emitted by a star per unit of time. It is an intrinsic property of the star and does not depend on its distance from the observer. Among the options:

• Magnitude: A measure of a star's brightness as seen from Earth (apparent magnitude) or absolute brightness (absolute magnitude).
• Luminosity: Correct; it is the total power of radiation emitted.
• Intensity: Refers to the power per unit area.
• Flux: The flow of energy per unit area per unit time.

Hence, the correct answer is "Luminosity".