Delmars Unit 20 Capacitance in AC Circuits
A 1 μF capacitor has 2,652 Ω of reactance at 60 Hz. What is the reactance value at 400 Hz? 639.79 Ω 568.72 Ω 397.88 Ω 768.33 Ω
397.88 Ω
Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 60 Hz source. What is the total capacitive reactance? 7.96 Ω 53.05 Ω 42.04 Ω 23.16 Ω
53.05 Ω
A 35 μF capacitor is connected to a 60-Hz, 120 V supply. What is the XC of the capacitor? 75.79 Ω 93.43 Ω 83.2 Ω 80.33 Ω
75.79 Ω
The quality of a capacitor is found by Q = _____. PF XC/R R/XC W/VARs
R/XC
The voltage rating of a capacitor _____. is a minimum working voltage can be exceeded as long as the time is under one hour is only a suggested maximum should never be exceeded
should never be exceeded
When the voltage and current have _____ polarities in a pure capacitive circuit, the capacitor is discharging and the energy is returned to the circuit. opposite the same
opposite
What is the reactance of a 25 μF capacitor when the applied frequency is 400 Hz? 16.12 Ω 11.59 Ω 10.61 Ω 15.92 Ω
15.92 Ω
In a circuit containing a capacitor, the impressed voltage is _____ with the applied voltage. 180° out of phase 90° out of phase 270° out of phase in phase
180° out of phase
Two capacitors, a 20 μF and a 30 μF, are connected in series to a 60 Hz source. What is the total capacitive reactance? 333.16 Ω 221.04 Ω 253.05 Ω 117.96 Ω
221.04 Ω
Two capacitors, a 20 μF and a 30 μF, are connected in series to a 400 Hz source. What is the total capacitive reactance? 33.16 Ω 53.05 Ω 7.96 Ω 42.04 Ω
33.16 Ω
Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in parallel to a 60 Hz source. What is the total XC? 42.78 Ω 566.32 Ω 442.09 Ω 6.42 Ω
42.78 Ω
Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in series to a 60 Hz source. What is the total XC? 566.32 Ω 442.09 Ω 226.42 Ω 342.78 Ω
442.09 Ω
What is the reactance of a 10 pF capacitor when the applied frequency is 30 Hz? 530.52 Ω 200.36 Ω 612.83 Ω 325.76 Ω
530.52 Ω
Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in parallel to a 400 Hz source. What is the total XC? 6.42 Ω 44.09 Ω 42.78 Ω 56.32 Ω
6.42 Ω
Three capacitors, a 12 μF, a 20 μF, and a 30 μF, are connected in series to a 400 Hz source. What is the total XC? 42.78 Ω 36.42 Ω 52.09 Ω 66.32 Ω
66.32 Ω
Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 400 Hz source. What is the total capacitive reactance? 42.04 Ω 33.16 Ω 7.96 Ω 53.05 Ω
7.96 Ω
A capacitor is connected to a 240 V supply. An ammeter indicates 3 A. What is the capacitive reactance of the capacitor? 71 Ω 23 Ω 80 Ω 30 Ω
80 Ω
The power in a capacitor is reactive power. What is the unit for reactive power? W P VA VAR
VAR
Countervoltage presented by a capacitor is called _____. inductive reactance capacitive reactance capacitance inductance
capacitive reactance
When a capacitor is connected to a(n) _____ circuit, current appears to flow through the capacitor. AC DC
AC
The capacitive reactance of a capacitor is _____ proportional to frequency. directly inversely
inversely
In a pure capacitive circuit, the current _____ the applied voltage by _____. lags; 180° lags; 90° leads; 180° leads; 90°
leads; 90°
What is the unit for capacitive reactance? coulomb farad henry ohm
ohm