The Chandrasekhar limit is
A) the upper-mass limit for a white dwarf.
B) the temperature at which hydrogen fusion starts.
C) the point at which a planetary nebula forms.
D) the temperature at which helium fusion starts.
E) the lower-mass limit for a Type II supernova.
A
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If in a gas the opacity is high, then energy transport is by _____________
a. conduction b. convection c. radiation d. All of the other choices are correct.
Repeat Problem 9.26 part (b) and (c) but assume that condensation occurs on a 5 cm-OD horizontal tube.
GIVEN
? SO2 condensing on a horizontal tube
? Tube outside diameter (D) = 5 cm = 0.05 m
? Pressure (p) 490 kPa
? SO2 properties
FIND
(a) Condensate film thickness (S) at 1.3 cm from the bottom (x = L – 1.3 cm = 0.187 m)
(b) The average heat transfer coefficient (hc)
(c) The rate of condensation (m) in kg/h
ASSUMPTIONS
? Steady state
? Laminar condensate flow
? Vapor density is negligible compared to the liquid density
SKETCH
Which of the following was the most important for maintaining the Earth's stable climate over the time it took for large organisms to evolve?
A) sustained volcanic activity B) plate tectonics C) the Moon D) the cessation of the heavy bombardment phase E) underground sea vents
One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz, and the next higher harmonic has a frequency of 576 Hz. How long is the tube? The speed of sound in air is 343 m/s
A) 1.34 m B) 0.670 m C) 0.335 m D) 1.00 m E) 2.68 m