The Discovery of the Period-Luminosity Relationship for Variable Stars Allowed

question 12

Multiple Choice

The discovery of the period-luminosity relationship for variable stars allowed them to be used as standard candles.Who made this important discovery?

• A) Ejnar Hertzsprung
• B) Henrietta Leavitt
• C) Henry Norris Russell
• D) Harlow Shapley

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Definitions:

Conditioned Stimulus

A stimulus that was originally neutral but, after association with an unconditioned stimulus, leads to eliciting a conditioned response.

Classical Conditioning

A fundamental learning technique established by the association between an initially neutral stimulus and a naturally occurring stimulus, leading to a learned response.

Acquisition

In psychology, the initial stage of learning or conditioning during which a response is established.

Extinction

In psychology, the gradual weakening and eventual disappearance of a conditioned response.