AC - Unit 21

What is the reactance of a 25 mF capacitor when the applied frequency is 400 Hz?

15.92 W

Two capacitors, a 20 mF and a 30 mF, are connected in series to a 60 Hz source. The total capacitive reactance is _____.

221.04 W

Three capacitors, a 12 mF, a 20 mF, and a 30 mF, are connected in parallel to a 60 Hz source. The total XC is _____.

42.78 W

What is the reactance of a 10 pF capacitor when the applied frequency is 30 Hz?

530.52 W

Three capacitors, a 12 mF, a 20 mF, and a 30 mF, are connected in series to a 400 Hz source. The total XC is _____.

66.32 W

A 35 mF capacitor is connected to a 60-Hz, 120 V supply. What is the XC of the capacitor? a. 75.79 Ω b. 80.33 Ω c. 83.2 Ω d. 93.43 Ω

75.79 Ω

The unit of capacitive reactance is the _____. a. ohm b. coulomb c. henry d. farad

ohm

The voltage rating of a capacitor _____. a. is a minimum working voltage b. should never be exceeded c. is only a suggested maximum d. can be exceeded as long as the time is under one hour

should never be exceeded

In a circuit containing a capacitor, the impressed voltage is _____ with the applied voltage. a. 270° out of phase b. 90° out of phase c. 180° out of phase d. in phase

180° out of phase

Two capacitors, a 20 mF and a 30 mF, are connected in series to a 400 Hz source. The total capacitive reactance is _____.

33.16 W

A 1 mF capacitor has 2,652 W of reactance at 60 Hz. How much is the reactance at 400 Hz?

397.88 Ω

Three capacitors, a 12 mF, a 20 mF, and a 30 mF, are connected in series to a 60 Hz source. The total XC is _____.

442.09 W

Two capacitors, a 20 mF and a 30 mF, are connected in parallel to a 60 Hz source. The total capacitive reactance is _____.

53.05 W

Three capacitors, a 12 mF, a 20 mF, and a 30 mF, are connected in parallel to a 400 Hz source. The total XC is _____.

6.42 W

Two capacitors, a 20 mF and a 30 mF, are connected in parallel to a 400 Hz source. The total capacitive reactance is _____.

7.96 W

A capacitor is connected to a 240 V supply. An ammeter indicates 3 A. What is the capacitive reactance of the capacitor? a. 23 Ω b. 30 Ω c. 71 Ω d. 80 Ω

80 Ω

The power in a capacitor is reactive power. The unit of reactive power is the _____. a. VAR b. VA c. P d. W

VAR

The symbol for capacitive reactance is _____. a. L b. XC c. XL d. C

XC

When a capacitor is connected to a(n) _____ circuit, current appears to flow through the capacitor. a. DC b. AC

AC

The capacitive reactance of a capacitor is _____ proportional to frequency.

inversely

In a capacitor, the current _____ the applied voltage. a. is out of phase with b. is in phase with c. lags d. leads

leads

In a capacitor, the current _____ the applied voltage by _____. a. lags, 180° b. leads, 90° c. lags, 90° d. leads, 180°

leads, 90°