Deck 15: Rc Circuits

Question 1

The amount of total voltage applied to a capacitor affects its capacitive reactance.

Answer 1

False

Question 2

The susceptance of a given capacitor decreases as frequency increases.

Answer 2

False

Question 3

What is the phase angle of the current in the circuit in Figure ?

A) 60°
B) 90°
C) 45°
D) 180°

Answer 3

45°

Question 4

The true power delivered to the load in Figure is the power that does the work.

Question 5

The current in the circuit in Figure is:

A) 49.76 mA
B) 1.0 mA
C) 1.4 mA
D) 14 mA

Question 6

Impedance is defined as the total opposition to current in an AC circuit.

Question 7

The term impedance, applied to a circuit containing capacitance and resistance, is the phasor result of the resistance and capacitive reactance.

Question 8

In a parallel capacitive circuit, all capacitors have the same amount of charge on them.

Question 9

The current always leads the voltage in a series resistor capacitor circuit by 45°.

Question 10

In a series capacitive circuit, the smallest capacitor has the largest voltage drop.

Question 11

The reactive power in Figure 15-1 creates a loss in the form of heat.

Question 12

A 10 mF capacitor will have more capacitive reactance than a 20 mF capacitor in a 60 Hz circuit.

Question 13

The total current and phase angle in the circuit in Figure 15-3 expressed in polar form is:

A) 1.33, 222.6° mA
B) 4.47, 263.4° mA
C) 1.33, 2-22.6° mA
D) 4.93, 2-22.6° mA

Question 14

The current leads the voltage in a series resistor capacitor circuit.

Question 15

A High-pass filter rejects higher frequencies and passes lower frequencies.

Question 16

The voltage across the capacitor in Figure 15-3 is:

A) 11.7 V rms
B) 8.94 V rms
C) 7.07 V rms
D) n/XC

Question 17

If a capacitor generates heat, it is probably defective.

Question 18

The total current in the circuit in Figure is:

A) 1.33 mA
B) 49.3 mA
C) 13.3 mA
D) 4.47m

Question 19

The phase angle in the circuit in Figure 15-3 is:

A) 11.94°
B) -11.94°
C) -22.6°
D) 63.4°

Question 20

What is the sine of the phase angle in the circuit in Figure ?

A) 0.57
B) 1.0
C) 0.333
D) 0.707

Question 21

A series circuit has an applied voltage of 100 V240° and a current of 1 A210°. Determine ZT) total impedance and express in rectangular form.

A) 100 Ω + j50 Ω
B) 100 Ω + j30 Ω
C) 64.3 Ω + j76.6 Ω
D) 86.6 Ω + j50 Ω

Question 22

What is the impedance of the circuit in Figure ?

A) 10 kΩ
B) 25 kΩ
C) 2.03 kΩ
D) 5.897 kΩ

Question 23

The voltage across the resistor in Figure 15-3 is:

A) 11.7 V rms
B) 7.07 V rms
C) n/XC
D) 4.47 V rms

Question 24

Which of the following expresses the impedance Z correctly in Figure in both rectangular and polar form?

A) 1.88-j.78, 2.03 -22.5°
B) 1.88-j.78, 7.07 11ec81bf_ec6d_acdc_bc38_29a3f7414e20_TB34225555_11 45°
C) 1.88+j.78, 2.03 11ec81bf_ec6d_acdc_bc38_29a3f7414e20_TB34225555_11 -22.5°kΩ
D) 1.88-j.78, 2.03 11ec81bf_ec6d_acdc_bc38_29a3f7414e20_TB34225555_11 -22.5°kΩ

Question 25

Which of the following is the reference vector for parallel RC circuits?

A) V
B) R
C) I
D) C

Question 26

The True power delivered to the load in Figure 15-4 is:

A) I2R
B) 10.0 mW.
C) 4.46 mW
D) Both A and B are correct.

Question 27

Impedance equals the vector sum of:

A) R and I
B) R and XC
C) R and V
D) R and C.

Question 28

Express the impedance of a 10 µF capacitor at 60 Hz in rectangular form.

A) 0 Ω + j265.3 Ω
B) 265.3 Ω - j0 Ω
C) 0 Ω - j0.00377 Ω
D) 0 Ω - j265.3 Ω

Question 29

What is the phase angle of the impedance in the circuit in Figure 15-4?

A) 45°
B) 94.4°
C) -45°
D) -60°

Question 30

What is the susceptance of a 100 µF capacitor at 1000 Hz?

A) 104 S
B) 0.63 S
C) 1.59 S
D) 10-4 S

Question 31

What is the total current in a parallel circuit consisting of a 1.27 µF capacitor, and a 50 Ω resistor, with a 2.5 kHz, 10 Vac power supply?

A) 282 mA
B) 200 mA
C) 141 mA
D) 400 mA

Question 32

The Reactive power in the capacitor in Figure 15-4 is:

A) 10.0 mW
B) 10.0 mVAR.
C) I2XC
D) Both B and C are correct.

Question 33

The phase angle between the source voltage and the current in Figure 15-5 is:

A) 22.5 degrees
B) 90 degrees.
C) approximately zero degrees
D) approximately 60 degrees.

Question 34

The total circuit current in Figure 15-4 is:

A) 0.707 mA
B) 1.41 mA
C) 44.6 mA
D) 10.04 mA

Question 35

In a series RC circuit, impedance is:

A) always smaller than R
B) larger than R.
C) the same as R
D) none of the above.

Question 36

The Apparent power in the entire circuit in Figure 15-4 is:

A) 39.48 mVA
B) 14.1 mVA
C) 4.46 mVA
D) 19.9 mVA

Question 37

The frequency at which the capacitive reactance equals the resistance in a low-pass or high-pass filter is called
.

A) unity-gain frequency
B) gain bandwidth product
C) generator frequency
D) cutoff frequency

Question 38

The total circuit impedance in Figure is:

A) 22.4 kΩ
B) 4.46 kΩ
C) 7.07 kΩ
D) 0.144 kΩ

Question 39

What is the impedance of a RC circuit consisting of a 56 kΩ resistor in series with a 0.033 µF capacitor ata frequency of 450 Hz?

A) 57,016 Ω
B) 45,270 Ω
C) 66,730 Ω
D) 10,730 Ω

Question 40

In a two-branch parallel RC circuit, impedance is:

A) less than either branch's opposition to current.
B) more than the resistive branch value.
C) more than the capacitive reactance branch value.
D) equal to the value of R.

Question 41

Convert the following complex number from polar form to rectangular form: 40 V 2120°

A) 20 + j34.6V
B) -80 - j34.6V
C) 80 + j34.6V
D) -20 + j34.6V

Question 42

Convert the following complex number from rectangular form to polar form: 8 + j6

A) 10 2- 53.1°
B) 10 236.9°
C) 10 253.1°
D) 10 2- 36.9°

Question 43

Which one of the following values is equivalent to 5 + j3) 4 - j6)?

A) 38 + j18
B) 2 + j18
C) 38 - j18
D) 2 - j18

Question 44

See Figure 15-6. Which equation describes the total impedance ZT?

A) ZT = Z1 + ZT'
B) ZT = Z1 + Z3 + Z5 + Z6'
C) ZT = Z1 + Z2 " ZT')
D) ZT = Z1" Z2

Question 45

In an RC circuit, true power equals:

A) VS × I
B) I2 R
C) VT × RT
D) P
$\mathrm{P}$

Question 46

Multiply the following complex numbers: 25 2-36.9°) 14 267°)

A) 350 230.1°
B) 350 2103.9°
C) 11 230.1°
D) 350 2-30.1°

Question 47

See Figure 15-6. Which one of these statements is true?

A) IS = I3
B) I3 = I4 + I6
C) I4 = I6
D) I3 = I2 + I5

Question 48

Which one of the following rectangular values is equivalent to the polar form 20 255°?

A) 16.38 + j11.47
B) 11.47 + j16.38
C) 16.38 - j11.47
D) 11.17 - j16.38

Question 49

Multiply the following complex numbers: 5 + j3) 2 - j4)

A) 10 - j14
B) 22 + j14
C) 22 - j14
D) 22 + j26

Question 50

If the voltage v = 50 sin500t - 75° is applied across a 25 Ω resistor, which equation describes the resistor current?

A) 2 sin500t - 75°
B) 2 sin20t - 3°
C) 2 cos500t - 75°
D) 1250 sin500t - 75°

Question 51

The time required for a phasor to go through 2n radians is the of the sine wave.

A) period
B) angle
C) frequency
D) domain

Question 52

If E = 10 V 230° and IS = 5 A 210°, what is the total impedance ZT?

A) 32.1 Ω + j38.3 Ω
B) 0.47 Ω - j0.17 Ω
C) 1.88 Ω + j0.68 Ω
D) 38.3 Ω + j32.1 Ω

Question 53

Divide the following complex numbers: 100 227°) / 33 2-14.3°)

A) 0.33 212.7°
B) 3 241.3°
C) 3 212.7°
D) 0.33 241.3°

Question 54

Which one of the following polar values is equivalent to 30 + j40?

A) 70 236.9°
B) 70 253.1°
C) 50 253.1°
D) 50 236.9°

Question 55

Subtract the following complex numbers: 15 + j15) - 10 + j8)

A) 5 + j7
B) 25 + j23
C) 5 - j7
D) 25 - j7

Question 56

In an RC circuit, the power factor is referred to as:

A) apparent power factor
B) true power factor
C) leading power factor
D) lagging power factor

Question 57

Divide the following complex numbers: 10 + j5) / 2 + j4)

A) 40 + j30
B) 40 - j30
C) 2 - j1.5
D) 2 + j1.5

Question 58

Convert the following complex number from rectangular form to polar form: 40 + j30V

A) 50 V 2-36.87°
B) 40 V 2-53.1°
C) 40 V 245°
D) 50 V 236.87°

Question 59

Convert the following complex number from polar form to rectangular form: 200 2-45°

A) 100 -j100
B) 141 -jl41
C) 100 +j100
D) 141 +jl41

Question 60

Add the following complex numbers: 40 + j10 and 25 - j7

A) 15 + j3
B) 65 - j3
C) 65 + jl7
D) 65 + j3

Question 61

Which one of the following phasor domain expressions is equivalent to the time domain 50 sinY + 15°)?

A) 35.35 215°
B) 50 215°
C) 70.7 2-15°
D) 70.7 215°

Question 62

Subtract the following complex numbers: 20 2-30° - 10 230°

A) 17.3 260°
B) 17.3 2-60°
C) 10 20°
D) 10 2360°

Question 63

The phase shift oscillator uses equal component RC networks that produce a required degree phase shift.

A) four, 45
B) three, 180
C) four, 90
D) three, 90

Question 64

The j operator is considered a:

A) rotational vector
B) complex operator
C) rotational operator
D) polar vector

Question 65

Multiply the following complex numbers: 1000 2-30° × 200 2-20°

A) 1200 250°
B) 200,000 2-50°
C) 200,000 250°
D) 800 2-50°

Question 66

Add the following complex numbers: 75 + j18 and 50 - j9

A) 125 + j27
B) 125 + j9
C) 125 - j27
D) 25 - j9

Question 67

In the complex plane, the horizontal is called the and the vertical is called the .

A) angular axis, quadrant axis
B) real axis, imaginary axis
C) phasor axis, wavelength
D) imaginary axis, real axis

Question 68

Divide the following complex numbers: 500 240° ÷ 10 215°

A) 50 2-25°
B) 250 215°
C) 250 2-15°
D) 50 225°