The Diameter of the Black Hole Candidate Cygnus X-1 Has

question 53

Multiple Choice

The diameter of the black hole candidate Cygnus X-1 has been estimated by

• A) combining the amount of energy received at Earth per second with the distance to the source to estimate the total energy emitted per second.
• B) measuring how quickly it flickers in intensity.
• C) measuring how long it takes to block off the light from its companion star during an eclipse (i.e. ,as it passes in front of its companion star as seen from Earth).
• D) combining its distance with its angular diameter to find its physical size.

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Definitions:

Datum Feature Symbol

A symbol used in geometric dimensioning and tolerancing to specify a reference for measurements.

MMC

Maximum Material Condition; a feature size where it contains the maximum amount of material within the stated limits of size.

Perpendicularity

The state or condition of being perpendicular, meaning two lines or planes intersect at a right angle (90 degrees) to each other.

Tolerance of Form

Specifies the allowable deviation from the ideal shape of an object without specifying size, ensuring parts fit together correctly.