Chapter 24

Capacitive reactance XC is given by Question options: 1) 1/wC 2) wC 3) w/C 4) C/w 5) 1/w2C

1) 1/wC

In a parallel RLC circuit, where IR = IR, max sin(wt), the current through the inductor, IL, is Question options: 1) IL = -IL, max sin(wt). 2) IL = IL, max sin(wt). 3) IL = -IL, max cos(wt). 4) IL = IL, max cos(wt). 5) IL = IL, max tan(wt).

3) IL = -IL, max cos(wt).

An LC circuit is to have resonant oscillations at 5.0 MHz. Find the value of a capacitor which will work with a 1.0-mH inductor. Question options: 1) 2 mF 2) 1 mF 3) 0.02 mF 4) 1 pF 5) 40 pF

4) 1 pF

A 60-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with R = 10.0 W and L = 10.0 mH. The impedance is Question options: 1) 3.77 W. 2) 9.26 W. 3) 10.0 W. 4) 10.7 W. 5) 13.8 W.

4) 10.7 W.

A 230 000 V-rms powerline carries an average power PAV = 250 MW a distance of 200 km. If the total resistance of the cables is 10 ohms, what is the resistive power loss? Question options: 1) 1.0 MW 2) 2.5 MW 3) 5.4 MW 4) 12 MW 5) 10 kW

4) 12 MW

An incandescent lightbulb is rated at 100 Watts when plugged into a 110 V-rms household outlet. Calculate the resistance of the filament and the rms current. Question options: 1) 12.2W, 0.90 A (rms) 2) 10W, 1.0 A (rms) 3) 110W, 1.0 A (rms) 4) 121W, 0.90 A (rms) 5) 11W, 1.1 A (rms)

4) 121W, 0.90 A (rms)

A 60-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 W and C = 300 mF. The impedance is Question options: 1) 4.68 W. 2) 8.84 W. 3) 10.0 W. 4) 13.4 W. 5) 18.8 W.

4) 13.4 W.

An ideal step-down transformer has 200 primary turns and 50 secondary turns. If 440 volts (rms) is placed across the primary, what is the current in the secondary when the load resistance is 7 ohms? Question options: 1) 3.6 A (rms) 2) 7.3 A (rms) 3) 11.4 A (rms) 4) 15.7 A (rms) 5) 12.4 A (rms)

4) 15.7 A (rms)

At what frequency will a 50-mH inductor have a reactance XL = 700W? Question options: 1) 352 Hz 2) 777 Hz 3) 1.25 kHz 4) 2.23 kHz 5) 14 kHz

4) 2.23 kHz

A high-voltage powerline operates at 500 000 V-rms and carries an rms current of 500 A. If the resistance of the cable is 0.050W/km, what is the resistive power loss in 200 km of the powerline? Question options: 1) 250 kW 2) 500 kW 3) 1 Megawatt 4) 2.5 Megawatts 5) 250 Megawatts

4) 2.5 Megawatts

A 2-mF capacitor in series with a 2-kW resistor is connected to a 60-Hz ac source. Calculate the impedance of the circuit. Question options: 1) 1500 ohms 2) 1800 ohms 3) 2100 ohms 4) 2400 ohms 5) 8600 ohms

4) 2400 ohms

A primary current of 6 A exists in an ideal iron-core transformer at a primary voltage of 100 volts. If the current in the secondary is 0.75 A, calculate the output voltage. Question options: 1) 12.5 V 2) 40 V 3) 400 V 4) 800 V 5) 200 V

4) 800 V

In a parallel RLC circuit, where IR = IR, max sin(wt), the current through the capacitor, IC, is Question options: 1) IC = -IC, max sin(wt). 2) IC = IC, max sin(wt). 3) IC = -IC, max cos(wt). 4) IC = IC, max cos(wt). 5) IC = IC, max tan(wt).

4) IC = IC, max cos(wt).

A series RLC circuit has an impedance of 120W and a resistance of 64W. What average power is delivered to this circuit when Vrms = 90 volts? Question options: 1) 36 W 2) 100 W 3) 192 W 4) 360 W 5) 12 W

1) 36 W

A 60-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with R = 10.0 W and L = 10.0 mH. The power factor, cos f, is Question options: 1) -1.00. 2) -0.936. 3) +0.943. 4) +0.936. 5) +1.00.

4) +0.936

A 60-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 W and C = 300 mF. The power factor, cos f, is Question options: 1) -1.00. 2) -0.749. 3) +0.749. 4) +0.834. 5) +1.00.

3) +0.749.

A 0.5-H inductor is connected into a 110 V-rms 60-Hz voltage source, with an ammeter in series. What is the rms value of the current through the inductor? Question options: 1) 0.189 A (rms) 2) 0.292 A (rms) 3) 0.584 A (rms) 4) 1.19 A (rms) 5) 0.093 A (rms)

3) 0.584 A (rms)

What is the average power dissipation in an RLC series circuit with R = 10W, L = 0.1 H, C = 10 mF when driven at resonance by a 100 V-rms source? Question options: 1) 100 W 2) 500 W 3) 1000 W 4) 2 kW 5) 700 W

3) 1000 W

If R = 10 ohms, L = 0.1 henry, C = 10 mF, what is the resonant frequency for the parallel RLC-circuit? Question options: 1) 1000 Hz 2) 333 Hz 3) 159 Hz 4) 53 Hz 5) 500 Hz

3) 159 Hz

The voltage 8.00 sin (400t) is applied to a series RLC circuit, with R = 200W, L = 0.100 H, and C = 1.00 mF. What are the impedance Z and the phase angle q? Question options: 1) 200 W, -37° 2) 566 W, +87° 3) 2470 W, -85.4° 4) 2540 W, -88.8° 5) 393 W, -63°

3) 2470 W, -85.4°

An ac generator with peak voltage 100 volts is placed across a 10-W resistor. What is the average power dissipated? Question options: 1) 100 W 2) 150 W 3) 500 W 4) 1000 W 5) 2000 W

3) 500 W

If an R = 1-kW resistor, a C = 1-mF capacitor, and an L = 0.2-H inductor are connected in series with a V = 150 sin (377t) volts source, what is the maximum current delivered by the source? Question options: 1) 0.007 A 2) 27 mA 3) 54 mA 4) 0.308 A 5) 0.34 A

3) 54 mA

A transformer is to be designed to increase the 30 kV-rms output of a generator to the transmission-line voltage of 345 kV-rms. If the primary winding has 80 turns, how many turns must the secondary have? Question options: 1) 6 2) 70 3) 920 4) 9200 5) 12

3) 920

An electric heater draws an average power of 1100 Watts when plugged into a 110 V-rms outlet. Calculate the resistance of the heater and the rms current. Question options: 1) 11W, 10 A (rms) 2) 110W, 10 A (rms) 3) 10W, 11 A (rms) 4) 10W, 110 A (rms) 5) 0.09W, 11 A (rms)

1) 11W, 10 A (rms)

The primary winding of an electric train transformer has 400 turns and the secondary has 50. If the input voltage is 120V(rms) what is the output voltage? Question options: 1) 15 V (rms) 2) 30 V (rms) 3) 60 V (rms) 4) 2.4 V (rms) 5) 960 V (rms)

1) 15 V (rms)

At what frequency will a 12-mF capacitor have a reactance XC = 300W? Question options: 1) 44 Hz 2) 88 Hz 3) 176 Hz 4) 352 Hz 5) 278 Hz

1) 44 Hz

A 60-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 W and C = 300 mF. The peak current in the circuit is Question options: 1) 8.24 A. 2) 8.84 A. 3) 11.0 A. 4) 12.4 A. 5) 23.5 A.

1) 8.24 A.

Inductive reactance XL is given by Question options: 1) Lw 2) L/w 3) 1/Lw 4) w/L 5) w2L

1) Lw

A 10-mF capacitor is plugged into a 110 V-rms 60-Hz voltage source, with an ammeter in series. What is the rms value of the current through the capacitor? Question options: 1) 0.202 A (rms) 2) 0.415 A (rms) 3) 0.626 A (rms) 4) 0.838 A (rms) 5) 0.066 A (rms)

2) 0.415 A (rms)

Find the resonant frequency for a series RLC circuit where R = 10W, C = 5 mF, and L = 2 mH. Question options: 1) 998 Hz 2) 1.592 kHz 3) 2.45 kHz 4) 11.3 kHz 5) 2.53 kHz

2) 1.592 kHz

A 60-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with R = 10.0 W and L = 10.0 mH. The peak current in the circuit is Question options: 1) 0.963 A. 2) 10.3 A. 3) 11.0 A. 4) 11.9 A. 5) 29.2 A.

2) 10.3 A.

A step-up transformer has an input voltage of 110V(rms). There are 100 turns on the primary and 1500 on the secondary. What is the output voltage? Question options: 1) 1600 V (max) 2) 1650 V (rms) 3) 3260 V (max) 4) 165 kV (rms) 5) 7.3 V (rms)

2) 1650 V (rms)

What is the average power dissipation in a series RC circuit if R = 5 kW, C = 2 mF, and V = 170 cos (300t)? Question options: 1) 0.93 W 2) 2.60 W 3) 28.2 W 4) 157 W 5) 5.20 W

2) 2.60 W

The inductance of a tuning circuit of an AM radio is 4 mH. Find the capacitance of the circuit required for reception at 1200 kHz. Question options: 1) 2.1 pF 2) 4.4 pF 3) 21.2 pF 4) 43.4 pF 5) 27.6 pF

2) 4.4 pF

A current I = 3 sin (400 t) amperes flows in a series RL circuit in which L = 1 mH and R = 100W. What is the average power loss? Question options: 1) 225 W 2) 450 W 3) 980 W 4) 1.12 kW 5) 900 W

2) 450 W

An RLC series circuit has R = 100 ohms, C = 25 mF, and L = 0.16 H. For what angular frequency of an ac voltage is the current flow maximum? Question options: 1) 251 rad/s 2) 500 rad/s 3) 757 rad/s 4) 884 rad/s 5) 79.6 rad/s

2) 500 rad/s

In a typical transmission line, the current I is very small and the voltage V is very large. A unit length of line has resistance R. For a power line that supplies power to 10,000 households, we can conclude that Question options: 1) IV = I2R. 2) I = V/R. 3) IV < I2R. 4) IV > I2R. 5) I2R = 0.

4) IV > I2R.

An alternating current circuit has resistance R, inductance L and capacitance C in series with a voltage source. Which statement is correct? Question options: 1) The voltage across the capacitor leads the voltage across the inductor by 90°. 2) The voltage across the inductor leads the voltage across the capacitor by 90°. 3) The voltage across the inductor leads the voltage across the resistor by 180°. 4) The voltage across the inductor leads the voltage across the capacitor by 180°. 5) Both voltages lead the voltage across the resistor by 90°.

4) The voltage across the inductor leads the voltage across the capacitor by 180°.

Whenever the alternating current frequency in a series RLC circuit is halved, Question options: 1) the inductive reactance is doubled and the capacitive reactance is halved. 2) the inductive reactance is doubled and the capacitive reactance is doubled. 3) the inductive reactance is halved and the capacitive reactance is halved. 4) the inductive reactance is halved and the capacitive reactance is doubled. 5) the reactance of the circuit remains the same.

4) the inductive reactance is halved and the capacitive reactance is doubled.

The average power input to a series alternating current circuit is minimum when Question options: 1) there are only a resistor and capacitor in the circuit. 2) there are only a resistor and inductor in the circuit. 3) there is only a resistor in the circuit. 4) XL = XC and the circuit contains a resistor, an inductor and a capacitor. 5) there is only a capacitor in the circuit.

5) there is only a capacitor in the circui