Absolute visual magnitude is the:
A) apparent magnitude of a star observed from Earth.
B) luminosity of a star observed from a distance of 1000 pc.
C) apparent magnitude of a star observed from a distance of 10 pc.
D) luminosity of a star observed from Earth.
Question 2Which of the following statements is true of the main sequence region of a Hertzsprung-Russell (H-R) diagram?
A) It runs from the right edge of the diagram to the left edge.
B) It includes only 10 percent of all normal stars.
C) The hot main-sequence stars are more luminous than the cool main-sequence stars.
D) The stars that are not on the main sequence have the same nuclear reactions as the main-sequence stars.
Question 3If one of the intrinsically brightest stars in our sky were 10pc away from Earth, it would appear:
A) more than 10 times as bright as Earth at its brightest.
B) more than 25 times as bright as Venus at its brightest.
C) more than 10 times as bright as Venus at its brightest.
D) more than 25 times as bright as Earth at its brightest.
Question 4In the context of blackbody radiation, which of the following statements is true of stars?
A) Temperatures of stars cannot be estimated from their color.
B) Red stars are cool, and blue stars are hot.
C) Red stars are hot, and blue stars are cool.
D) Star temperatures cannot be measured using the relative strengths of various spectral lines.
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