When Does a Protostar Become a Main-Sequence Star

question 106

Multiple Choice

When does a protostar become a main-sequence star?

• A) When the rate of hydrogen fusion becomes high enough to balance the rate at which the star radiates energy into space
• B) When a piece of a molecular cloud first begins to contract into a star
• C) When it becomes luminous enough to emit thermal radiation
• D) At the instant that the first hydrogen fusion reactions occur in the protostar's core

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Definitions:

Net Income

The total earnings of a company after all expenses and taxes have been deducted from total revenue, often referred to as the bottom line.

Current Ratio

A liquidity ratio that measures a company’s ability to pay short-term obligations with its current assets.

Liquid

Describes assets that can be easily and quickly converted into cash without significant loss in value.

Quick Ratio

A liquidity measure that indicates a company's ability to pay its current liabilities without needing to sell inventory, calculated as (current assets - inventory) / current liabilities.