A Radio Astronomer Points a Radio Telescope Through the Milky

question 205

Multiple Choice

A radio astronomer points a radio telescope through the Milky Way's disk in a direction directly away from the center of the Galaxy.If the astronomer measures the Doppler shift of the 21-cm radio line of hydrogen from interstellar clouds at several different distances from the Sun along this line of sight,what should be the result? (Figure 13-7 of Comins,Discovering the Essential Universe,6th ed.,may be helpful.)

• A) The Doppler shift should have a constant value, regardless of distance, as a result of the Sun's speed of motion around the center of the Galaxy.
• B) The Doppler shift should be almost zero for all clouds, regardless of distance.
• C) The Doppler shift should rise to a maximum at some distance, then decrease again.
• D) The Doppler shift should be larger the farther away the cloud is.

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Definitions:

A-B-C Analysis

The process of keeping a log of the antecedents, behavior, and consequences for a particular student in order to pinpoint a problem and the circumstances that elicit and maintain it.

Reinforcement

The process of encouraging or establishing a pattern of behavior by offering rewards or positive outcomes.

Punishment

A concept in behavioral psychology where an unpleasant consequence follows a behavior, with the aim of decreasing or stopping that behavior.

Subjective Terms

Concepts or descriptors that are influenced by personal feelings, opinions, or experiences, lacking objective or universally accepted standards.