The universe is said to be closed if I. gravity is strong enough to stop the expansion in a finite time. II. the density of the universe is less than the critical density. III. the universe is finite
a. I & II
b. I & III
c. II & III
d. I, I, & III
e. none of the above
B
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The quantum numbers of electrons on an atom include the principal quantum number, the angular-momentum quantum number, the magnetic quantum number, and the ______________quantum number of +/–1/2.
Fill in the blank(s) with the appropriate word(s).
Astronomers determine the internal structure of a star by using stellar models, since they cannot "see" into the interior of a star
a. True b. False Indicate whether the statement is true or false
Energy and Mass: In a nuclear plant, 1017 J of energy is available from mass conversion. How much mass of fuel was lost to produce this energy? (c = 3.0 × 108 m/s)
A. 0.1 kg B. 1 kg C. 10 kg D. 100 kg
A proton is projected with a velocity of 7.0 × 103 m/s into a magnetic field of 0.60 T perpendicular to the motion of the proton. What is the force that acts on the proton?
A) 0 N B) 3.4 × 10-16 N C) 4.2 × 10-16 N D) 13 × 10-16 N E) 6.7 × 10-16 N