Chapter Review Questions Flashcards
The average power absorbed by an inductor is zero
True
The Thevinin impedance of a network seen from the load terminals is 80 +j55. For maximum power transfer the load impedance must be
80-j55
The amplitude if the voltage available in the 60 Hz, 120V power outlets in your home is
170
If the load impedance is 20-j20 the power factor is
0.7071
A quantity that contains all the power information in a given load is the
Complex power
Reactive power is measured in
VAR
Power symbols and power types
Real (P)
Reactive (Q)
Apparent (S)
A source is connected to three loads Z1 Z2 and Z3 in parallel.
S != S1+S2+S3
The instrument for measuring apparent power is the
Wattmeter
The principal of superposition applies to power calculations
False
For superposition it is not required that only one independent source can be considered at a time; any number of independent sources can be considered simultaneously
True
The source is applying the maximum power to the load when the load resistance equals the source resistance
True
What charge is on a 5F capacitor when it is connected across a 120V source
600
Capacitance is measured in
Farads
When the total charge in a capacitor is doubled the energy stored
Is quadrupled
The total capacitance of two 40mF series connected capacitors in parallel with a 4mF capacitor is
24
A 5H inductor changes ots current by 3A in 0.2s the voltage produced at the terminals if the inductor is
75
If the current through a 10mH inductor increases from zero to 2A. How much energy is stored in the resistor
28mJ
Inductors in parallel can be combined just like resistors in parallel
True
