The temperature of the innermost part of the spinning gas near our galaxy's central black hole is:
A) 2.7 K.
B) 300 K.
C) 10,000 K.
D) over 1,000,000 K.
E) varying rapidly from 300 K to 1,000,000 K.
D
You might also like to view...
A particle moves east at constant velocity v r for a time interval ?T. It then moves north at a constant velocity, with the same speed as before, for another time interval ?T. Finally it moves east again with the original velocity. At the instant an additional time interval ?T has elapsed, which of the following are true about the average velocity and the average acceleration for the motion described?
a. The average velocity is v r and the average acceleration is zero. b. The average velocity is v r and the average acceleration is not zero. c. The average velocity is not v r and the average acceleration is zero. d. The average velocity is not v r and the average acceleration is not zero.
Phase Angles: A series ac circuit has a resistance of 2.0 k?, a capacitance of 8.0 ?F, and an inductance of 9.0 H. If the frequency of the alternating current is 4.0/? kHz, by what angle does the voltage lead the current?
A. +1.5 rad B. -1.8 rad C. +36 rad D. +3.1 rad E. -3.1 rad
Which of the following best describes why the Sun emits most of its energy in the form of visible light?
A) Like all objects, the Sun emits thermal radiation with a spectrum that depends on its temperature, and the Sun's surface temperature is just right for emitting mostly visible light. B) Nuclear fusion in the Sun's core produces visible light photons. C) The visible light comes from energy level transitions as electrons in the Sun's hydrogen atoms jump between level 1 and level 2. D) The Sun's gas is on fire like flames from wood or coal, and these flames emit visible light.
Which spacecraft launched a probe that smashed into comet Tempel 1?
A. NEAR B. Deep Impact C. Hayabusa D. Stardust