Why Do O- and B-Type Stars Have Weaker Hydrogen Absorption

question 56

Multiple Choice

Why do O- and B-type stars have weaker hydrogen absorption lines than A-type stars?

• A) O- and B-type stars are cooler than A-type stars.
• B) O- and B-type stars are smaller than A-type stars.
• C) A larger fraction of hydrogen atoms in O- and B-type stars is ionized.
• D) O- and B-type stars have converted much more of their hydrogen into heavier elements.
• E) A-type stars have a higher mass than O- and B-type stars, so they have more hydrogen.

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Definitions:

Face Validity

The extent to which a test is subjectively viewed as covering the concept it purports to measure, often assessed through its appearance to non-experts.

Predictive Validity

The extent to which a score on a test or measurement accurately predicts future performance on a related task or behavior.

Concurrent Validity

The degree to which the results of a particular test or measurement correspond to those of a previously established measurement for the same construct.

Content Validity

The extent to which a test measures all aspects of the concept or construct it intends to assess, ensuring that the test is fully representative.