Which of the following is not true of quasars?
A) Quasars were more common in the past.
B) The light produced by quasars comes from an accretion disk surrounding a supermassive black hole.
C) Quasars are powered by the intense production of large numbers of stars that can only be sustained for a relatively short time.
D) Some quasars can change their brightness on the timescale of hours.
E) Some quasars are more than a thousand times more luminous than the Milky Way.
C
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An ideal fluid in a pipe of diameter 14. cm is moving at 6.0 m/s
(a) If the incompressible fluid density is 1.05 grams/cc, what is the flow rate in kg/s? (b) What is the speed of flow if the pipe narrows to 4.0 cm radius?
Jupiter and the other jovian planets are sometimes called "gas giants." In what sense is this term misleading?
A) The materials they are made of are not the kinds of thing we usually think of as gases. B) They actually contain relatively little material in a gaseous state. C) Actually, it's a great description, because these worlds are big and gaseous throughout. D) They are not in any sense "giants."
It was because the health effects of the Three Mile Island accident in 1979 were so severe that it caused general public alarm
What will be an ideal response?
A fully charged parallel-plate capacitor remains connected to a battery while you slide a dielectric between the plates. What happens to the value of C?
1.It increases. 2.It decreases. 3.It stays the same.