In a photo like the Hubble Deep Field (Figure 20.1 in your textbook), we see galaxies in many different stages of their lives. In general, which galaxies are seen in the earliest (youngest) stages of their lives?
A) the galaxies that are farthest away
B) the galaxies that have the most hot, young O and B stars
C) the galaxies that are the reddest in color
D) the galaxies that are nearest to us
A
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Exclusion Principle: Consider ground-state helium having two electrons in orbit. If one of the electrons has quantum numbers (n, ?l, m1, ms) of 1, 0, 0, -1/2 respectively, the quantum numbers for the other electron will be
A. 1, 1, 0, -1/2. B. 1, 0, 0, +1/2. C. 1, 1, 1, +1/2. D. none of the given answers.
Collisions between galaxies are thought to:
A) have stopped about 5 billion years ago. B) be commonplace. C) have never occurred. D) be extremely rare. E) have only occurred between 10 and 15 billion years ago.
Assuming negligible friction, what spring constant would be needed by the spring in a "B-B gun" to fire a 10. gram pellet to a height of 100 meters if the spring is initially compressed 10. cm?
A) 20. N/cm B) 20. N/m C) 200. N/m D) 2.0 × 103 N/cm E) 2.0 × 10-3 N/m
The volume of a sphere is 8.00 m3 . The radius of the sphere is
A. 1.24 m. B. 2.00 m. C. 2.65 m. D. 3.00 m.