In an AC circuit operating at a frequency where the phase angle with respect to the current is 30°, what happens to the phase angle if the capacitance of the circuit is increased?
a. It increases. b. It decreases.
c. nothing d. It decreases and can become zero.
a
You might also like to view...
In a binary system, the more massive star
a. is at the center of mass. b. is farthest from the center of mass. c. is nearest the center of mass. d. follows the largest orbit. e. shows a larger Doppler shift in its spectral lines.
Air at 16°C and atmospheric pressure enters a 1.25-cm-ID tube at 30 m/s. For an average wall temperature of 100°C, determine the discharge temperature of the air and the pressure drop if the pipe is (a) 10-cm-long and (b) 102-cm-long.
GIVEN
• Atmospheric air flowing through a tube
• Entering air temperature (Tb,in) = 16°C
• Tube inside diameter (D) = 1.25 cm = 0.0125 m
• Air velocity (V) = 30 m/s
• Average wall surface temperature (Ts) = 100°C
FIND
The discharge temperature (Tb,out) and the pressure drop (?p) if the pipe length (L) is
(a) 10 cm (0.1 m) (b) 102 cm (1.02 m)
ASSUMPTIONS
• Steady state
• The tube is smooth
SKETCH
for dry air at the entering bulk temperature of 16°C
Density (?) = 1.182 kg/m3
Thermal conductivity (k) = 0.0248 W/(m K)
Kinematic viscosity (?) = 15.3 × 10–6 m2/s
Prandtl number (Pr) = 0.71
Specific heat (c) = 1012 J/(kg K)
What is the name of the nearest large spiral galaxy to our own Milky Way, in the Local Group?
A: The Large Magellanic Cloud. B: The Small Magellanic Cloud. C: The Sagittarius Dwarf. D: The Andromeda Galaxy. E: The Virgo Cluster.
An object moves 10 m east in 30 s and then returns to its starting point taking an additional 50 s. If west is chosen as the positive direction, what is the sign associated with the average velocity of the object?
a. + b. ? c. 0 (no sign) d. any of the above