The X-Ray Source Cygnus X-1 Is a Black Hole Candidate

question 65

Multiple Choice

The X-ray source Cygnus X-1 is a black hole candidate located in a binary star system. The X-ray source is believed to occupy a volume smaller than Earth. This size is deduced from

• A) rapid flickering in the X-ray brightness of Cygnus X-1.
• B) Cygnus X-1's apparent magnitude and distance.
• C) Cygnus X-1's luminosity and spectral class.
• D) the shortness of Cygnus X-1's orbital period.

---

Definitions:

Overhead Volume Variance

The difference between the budgeted overhead cost and the applied overhead cost based on actual activity levels.

Labor Price Variance

The difference between the actual cost of labor and the budgeted or standard cost of labor, used in budgeting and cost management.

Materials Quantity Variance

The difference between the actual quantity of materials used in production and the expected amount, which can indicate efficiency or waste.

Standard Price

The predetermined cost assigned to materials, labor, and overhead, used in budgeting and variance analysis.