Study this H-R diagram. What is the spectral type of the star Sirius? (The red arrow helps you locate Sirius on the diagram.)
A) A
B) 102
C) main sequence
D) blue
A) A
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Granitic pebbles with a radiometric age of 300 million years are embedded in a sedimentary rock. A dike, dated at 200 million years, intrudes into the sedimentary rock
With all this information we can estimate the age of the sedimentary rock to be A) older than 300 million years. B) younger than 200 million years. C) between 200 and 300 million years old. D) precisely 300 million years old.
Which of the following happens when a star runs out of hydrogen at its center?
A) The core of the star expands. B) The outer layers of the star heat up. C) The star moves toward the lower left in the Hertzsprung-Russell diagram. D) The stellar core becomes almost pure helium
An object is 80 cm in front of a lens. An image forms 10 cm behind the lens. The lateral magnification
A) is -8. B) is -0.125. C) is 8. D) is 0.125. E) cannot be determined with the information given.
Suppose you receive a message from a starbase that is 13.0 light-years from earth. The message is dated July 15, 2127. What year does your calendar indicate at the time of reception if your calendar and the station’s calendar are correctly synchronized?
A. 2127 B. 2114 C. 2140 D. Other (specify)