Question 1

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

Accepted Answer

A)  200.36 Ω 
B)  325.76 Ω 
C)  530.52 Ω 
D)  612.83 Ω 
A)  200.36 Ω 
B)  325.76 Ω 
C)  530.52 Ω 
D)  612.83 Ω C

Question 2

A 35 μF capacitor is connected to a 60-Hz, 120 V supply. What is the XC of the capacitor?

Accepted Answer

A)  75.79 Ω 
B)  80.33 Ω 
C)  83.2 Ω 
D)  93.43 Ω 
A)  75.79 Ω 
B)  80.33 Ω 
C)  83.2 Ω 
D)  93.43 Ω A

Question 3

Countervoltage presented by a capacitor is called .

Accepted Answer

A)  capacitance 
B)  inductance 
C)  capacitive reactance 
D)  inductive reactance 
A)  capacitance 
B)  inductance 
C)  capacitive reactance 
D)  inductive reactance C

Question 4

The power in a capacitor is reactive power. What is the unit for reactive power?

Accepted Answer

A)  W 
B)  VA 
C)  P 
D)  VAR 
A)  W 
B)  VA 
C)  P 
D)  VAR

Question 5

In a pure capacitive circuit, the current the applied voltage by .

Accepted Answer

A)  leads; 180° 
B)  lags; 180° 
C)  leads; 90° 
D)  lags; 90° 
A)  leads; 180° 
B)  lags; 180° 
C)  leads; 90° 
D)  lags; 90°

Question 6

Two capacitors, a 20 μF and a 30 μF, are connected in series to a 60 Hz source. What is the total capacitive reactance?

Accepted Answer

A)  117.96 Ω 
B)  221.04 Ω 
C)  253.05 Ω 
D)  333.16 Ω 
A)  117.96 Ω 
B)  221.04 Ω 
C)  253.05 Ω 
D)  333.16 Ω

Question 7

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?

Accepted Answer

A)  226.42 Ω 
B)  342.78 Ω 
C)  442.09 Ω 
D)  566.32 Ω 
A)  226.42 Ω 
B)  342.78 Ω 
C)  442.09 Ω 
D)  566.32 Ω

Question 8

The capacitive reactance of a capacitor is proportional to frequency.

Accepted Answer

A)  directly 
B)  inversely 
A)  directly 
B)  inversely

Question 9

The voltage rating of a capacitor .

Accepted Answer

A)  can be exceeded as long as the time is under one hour 
B)  should never be exceeded 
C)  is only a suggested maximum 
D)  is a minimum working voltage 
A)  can be exceeded as long as the time is under one hour 
B)  should never be exceeded 
C)  is only a suggested maximum 
D)  is a minimum working voltage

Question 10

In a circuit containing a capacitor, the impressed voltage is with the applied voltage.

Accepted Answer

A)  180° out of phase 
B)  90° out of phase 
C)  in phase 
D)  270° out of phase 
A)  180° out of phase 
B)  90° out of phase 
C)  in phase 
D)  270° out of phase

Question 11

Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 60 Hz source. What is the total capacitive reactance?

Accepted Answer

A)  7.96 Ω 
B)  23.16 Ω 
C)  42.04 Ω 
D)  53.05 Ω 
A)  7.96 Ω 
B)  23.16 Ω 
C)  42.04 Ω 
D)  53.05 Ω

Question 12

A capacitor is connected to a 240 V supply. An ammeter indicates 3 A. What is the capacitive reactance of the capacitor?

Accepted Answer

A)  23 Ω 
B)  30 Ω 
C)  71 Ω 
D)  80 Ω 
A)  23 Ω 
B)  30 Ω 
C)  71 Ω 
D)  80 Ω

Question 13

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

Accepted Answer

A)  10.61 Ω 
B)  11.59 Ω 
C)  15.92 Ω 
D)  16.12 Ω 
A)  10.61 Ω 
B)  11.59 Ω 
C)  15.92 Ω 
D)  16.12 Ω

Question 14

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

Accepted Answer

A)  DC 
B)  AC 
A)  DC 
B)  AC

Question 15

Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 400 Hz source. What is the total capacitive reactance?

Accepted Answer

A)  7.96 Ω 
B)  33.16 Ω 
C)  42.04 Ω 
D)  53.05 Ω 
A)  7.96 Ω 
B)  33.16 Ω 
C)  42.04 Ω 
D)  53.05 Ω

Question 16

The quality of a capacitor is found by Q = .

Accepted Answer

A)  XC/R 
B)  R/XC 
C)  PF 
D)  W/VARs 
A)  XC/R 
B)  R/XC 
C)  PF 
D)  W/VARs

Question 17

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?

Accepted Answer

A)  6.42 Ω 
B)  42.78 Ω 
C)  442.09 Ω 
D)  566.32 Ω 
A)  6.42 Ω 
B)  42.78 Ω 
C)  442.09 Ω 
D)  566.32 Ω

Question 18

What is the unit for capacitive reactance?

Accepted Answer

A)  ohm 
B)  farad 
C)  henry 
D)  coulomb 
A)  ohm 
B)  farad 
C)  henry 
D)  coulomb

Question 19

A 1 μF capacitor has 2,652 Ω of reactance at 60 Hz. What is the reactance value at 400 Hz?

Accepted Answer

A)  397.88 Ω 
B)  568.72 Ω 
C)  639.79 Ω 
D)  768.33 Ω 
A)  397.88 Ω 
B)  568.72 Ω 
C)  639.79 Ω 
D)  768.33 Ω

Question 20

What is the symbol for capacitive reactance?

Accepted Answer

A)  C 
B)  XC 
C)  L 
D)  XL 
A)  C 
B)  XC 
C)  L 
D)  XL

Exam 21: Capacitance in Alternating Current Circuits

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

A 35 μF capacitor is connected to a 60-Hz, 120 V supply. What is the XC of the capacitor?

Countervoltage presented by a capacitor is called .

The power in a capacitor is reactive power. What is the unit for reactive power?

In a pure capacitive circuit, the current the applied voltage by .

Two capacitors, a 20 μF and a 30 μF, are connected in series to a 60 Hz source. What is the total capacitive reactance?

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?

The capacitive reactance of a capacitor is proportional to frequency.

The voltage rating of a capacitor .

In a circuit containing a capacitor, the impressed voltage is with the applied voltage.

Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 60 Hz source. What is the total capacitive reactance?

A capacitor is connected to a 240 V supply. An ammeter indicates 3 A. What is the capacitive reactance of the capacitor?

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

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

Two capacitors, a 20 μF and a 30 μF, are connected in parallel to a 400 Hz source. What is the total capacitive reactance?

The quality of a capacitor is found by Q = .

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?

What is the unit for capacitive reactance?

A 1 μF capacitor has 2,652 Ω of reactance at 60 Hz. What is the reactance value at 400 Hz?

What is the symbol for capacitive reactance?

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