Exam-style question
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How does the luminosity of a quasar relate to its distance from Earth?.
- A.Luminosity increases with distance.
- B.Luminosity remains constant regardless of distance.
- C.Luminosity decreases with distance.
- D.Luminosity is only relevant for nearby quasars.
Model answer
What a good answer should say
- Luminosity decreases with distance.
Explanation
Why this works
As the distance from a quasar increases, the observed brightness decreases due to the inverse square law of light. This means that while the intrinsic luminosity remains constant, the apparent brightness diminishes with distance, which can be used to infer distance in cosmological studies.
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