Cepheid variable stars have pulsation periods of _____
A) 1 to 60 days
B) 80 to 140 days
C) 150 to 210 days
D) 230 to 290 days
A
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The ______________electrons of an atom are the electrons in an incomplete electron shell that are outside of a spherically symmetric closed electron shell corresponding to an inert-gas atom.
Fill in the blank(s) with the appropriate word(s).
Helioseismology maps of rotation in the Sun's interior show that its internal gases rotate with equal periods
a. True b. False Indicate whether the statement is true or false
The Gateway Arch in St. Louis is approximately 193 meters tall. What is its height in feet?
A) 58.8 feet B) 64.3 feet C) 633 feet D) 759 feet E) 7,590 feet
What prevents a large piece of uranium ore from going naturally into a chain reaction?
a. Because none of its nuclei fission without bombardment from human-controlled sources. b. Because even a small chunk is too large to sustain a chain reaction. c. Because the sample is not large enough to capture many neutrons. d. Because there isn't enough uranium for fissioning neutrons to trigger another reaction. e. Because so many of its fissioning neutrons are captured by uranium-238 which then decays in other ways.