Question

when light from a hot dense energy source, like a star, passes through a cool cloud of gas, we see
a an absorption line spectrum
b an emission line spectrum
c a continuous line spectrum
d infrared light

Explanation:

Step1: Understand spectrum types

• A continuous spectrum has all wavelengths without gaps.
• An emission spectrum emits specific wavelengths.
• An absorption spectrum has dark lines (absorbed wavelengths).

Step2: Analyze the scenario

When light from a hot source (like a star) passes through a cool gas cloud, the cool gas absorbs certain wavelengths. This results in an absorption line spectrum as the absorbed wavelengths are missing (seen as dark lines) in the spectrum we observe.

Answer:

A. an absorption line spectrum