Question 1

The current-limiting property of an inductor is called _____.
A) resistance
B) inductance
C) reactance
D) henrys

Accepted Answer

The current-limiting property of an inductor is referred to as reactance, specifically inductive reactance, which opposes changes in current.

Question 2

The unit of inductance is the _____.
A) reactance
B) henry
C) ohm
D) hertz

Accepted Answer

The unit of inductance is the henry, symbolized as H, which measures the amount of magnetic flux generated for a given electric current flow.

Question 3

An inductor is connected to a 60 Hz circuit. The inductive reactance is 75.4 Ω . What is the inductance of the inductor?
A) 0.2 H
B) 5 H
C) 284 H
D) 4524 H

Accepted Answer

The inductive reactance (X_L) is given by the formula X_L = 2πfL, where f is the frequency and L is the inductance. Rearranging for L gives L = X_L / (2πf). Substituting the given values (X_L = 75.4 Ω, f = 60 Hz) into the formula yields L ≈ 0.2 H.

Question 4

Two inductors are connected in parallel to a 120-V, 60-Hz supply. The values of the inductors are 0.15 H and 0.225 H. The total inductive reactance is _____.
A) 3.54 A
B) 4.84 A
C) 5.41 A
D) 6.12 A

Accepted Answer

The answer of Two inductors are connected in parallel to...

Question 5

Two inductors are connected in series to a 120-V, 60-Hz supply. The values of the inductors are 1.5 H and 2.5 H. The total inductive reactance is _____.
A) 42.5 Ω
B) 365.5 Ω
C) 553.44 Ω
D) 1508 Ω

Accepted Answer

The answer of Two inductors are connected in series to...

Question 6

An inductor is connected to a 120-V, 60-Hz supply. The current in the circuit is 2.4 A. What is the inductive reactance?
A) 57.08 Ω
B) 104.8 Ω
C) 288 Ω
D) 50  Ω

Accepted Answer

The answer of An inductor is connected to a 120-V,...

Question 7

The symbol for reactive power of an inductor is _____.
A) W
B) VA
C) VARs
D) P

Accepted Answer

The symbol for reactive power, especially in the context of an inductor, is VARs (Volt-Ampere Reactive). Reactive power is the imaginary component of power in AC circuits, and VARs specifically denote this aspect, distinguishing it from real power (measured in watts) and apparent power (measured in volt-amperes).

Question 8

An inductor with an inductance of three henrys (H) is to be connected to a 60 Hz circuit. What will the inductive reactance be?
A) 180 Ω
B) 360 Ω
C) 565 Ω
D) 1131 Ω

Accepted Answer

The answer of An inductor with an inductance of three...

Question 9

In a pure inductive circuit, current _____.
A) lags voltage by 90 °
B) leads voltage by 90 °
C) is in phase with voltage
D) lags voltage by 180 °

Accepted Answer

In a pure inductive circuit, the current lags the voltage by 90 degrees due to the property of inductors to resist changes in current.

Question 10

Circuits are generally considered to contain _____ when any type of load that contains a coil is used.
A) inductance
B) reactance
C) resistance
D) volt-amperes

Accepted Answer

When a load contains a coil, it introduces inductance into the circuit, as coils are inductive components.

Question 11

An inductor is connected to a 240-V, 60-Hz supply. The current in the circuit is 5 A. What is the inductance of the inductor?
A) .0048 H
B) .0075 H
C) .1185 H
D) .127 H

Accepted Answer

The answer of An inductor is connected to a 240-V,...

Question 12

Two inductors are connected in parallel to a 120-V, 60-Hz supply. The values of the inductors are 1.5 H and 2.5 H. The total inductive reactance is _____.
A) 525.5 Ω
B) 533.49 Ω
C) 942.5 Ω
D) 1508 Ω

Accepted Answer

The total inductive reactance (X_total) of inductors in parallel can be found using the formula for parallel reactances: 1/X_total = 1/X_1 + 1/X_2, where X_1 and X_2 are the reactances of the individual inductors. The reactance of an inductor is given by X = 2πfL, where f is the frequency and L is the inductance. For the 1.5 H inductor, X_1 = 2π(60)(1.5) = 565.5 Ω. For the 2.5 H inductor, X_2 = 2π(60)(2.5) = 942.5 Ω. Using the parallel reactance formula: 1/X_total = 1/565.5 + 1/942.5, solving for X_total gives approximately 533.49 Ω.

Question 13

An inductor has an inductive reactance of 64 Ω , and a wire resistance of 36 Ω . What is the impedance of the inductor?
A) 10 Ω
B) 28 Ω
C) 73.4 Ω
D) 82.92 Ω

Accepted Answer

The impedance of an inductor is calculated using the formula $Z = \sqrt{R^2 + X_L^2}$, where $Z$ is the impedance, $R$ is the resistance, and $X_L$ is the inductive reactance. Substituting the given values, $Z = \sqrt{36^2 + 64^2} = \sqrt{1296 + 4096} = \sqrt{5392} ≈ 73.4 \Omega$.

Question 14

When a magnetic field continually changes magnitude and direction, a voltage is continually being induced in the coil. This voltage is called _____ voltage.
A) conducted
B) induced
C) applied
D) inductive

Accepted Answer

The voltage generated in a coil by a changing magnetic field is known as induced voltage, aligning with Faraday's law of electromagnetic induction.

Question 15

The total current-limiting effect is called _____.
A) reluctance
B) impedance
C) resistive reactance
D) inductive resistance

Accepted Answer

Impedance is the total opposition to the flow of electric current, combining both resistance and reactance (which includes capacitive and inductive effects), thus representing the total current-limiting effect in an AC circuit.

Question 16

The amount of resistance compared with the inductive reactance determines the _____ of the coil.
A) power factor (PF)
B) quality (Q)
C) phase angle ( θ )
D) reactance (X)

Accepted Answer

The quality (Q) of a coil is determined by the amount of resistance compared with the inductive reactance. This quality factor indicates how underdamped an oscillator or resonator is, and characterizes a resonator's bandwidth relative to its center frequency.

Question 17

The symbol for reactance is _____. A) R _L B) X _L C) L D) H

Accepted Answer

The symbol for reactance is represented by the letter "X". Reactance is a component of impedance in AC circuits, encompassing both inductive reactance (X_L) and capacitive reactance (X_C).

Question 18

The symbol X_L stands for _____. A) resistance B) inductive resistance C) inductive reactance D) resistive reactance

Accepted Answer

The symbol X_L stands for inductive reactance. Inductive reactance is the opposition to the change of current by an inductor in an AC circuit.

Question 19

Two inductors are connected in series to a 120-V, 60-Hz supply. The values of the inductors are 0.175 H and 0.255 H. The total circuit current is _____.
A) 0.74 A
B) 1.02 A
C) 1.85 A
D) 3.067 A

Accepted Answer

The total inductance in series is the sum of the individual inductances, which is $0.175 \, \text{H} + 0.255 \, \text{H} = 0.43 \, \text{H}$. The inductive reactance $X_L$ is given by $X_L = 2\pi fL$, where $f = 60 \, \text{Hz}$ and $L = 0.43 \, \text{H}$. Thus, $X_L = 2\pi \times 60 \times 0.43 \approx 161.57 \, \Omega$. The current $I$ can be found using Ohm's Law for AC circuits, $I = \frac{V}{X_L}$, where $V = 120 \, \text{V}$. Therefore, $I = \frac{120}{161.57} \approx 0.74 \, \text{A}$.

Question 20

Volt-amperes-reactive is used to measure the _____ in a pure inductive circuit.
A) watts
B) reactive power
C) volt amperes
D) joules

Accepted Answer

Reactive power in AC circuits is measured in volt-amperes-reactive (VAR), which quantifies the non-working power generated by reactive components like inductors and capacitors.

Quiz 17: Inductance in Alternating Current Circuits

The current-limiting property of an inductor is called _____.

The unit of inductance is the _____.

An inductor is connected to a 60 Hz circuit. The inductive reactance is 75.4 Ω . What is the inductance of the inductor?

Two inductors are connected in parallel to a 120-V, 60-Hz supply. The values of the inductors are 0.15 H and 0.225 H. The total inductive reactance is _____.

Two inductors are connected in series to a 120-V, 60-Hz supply. The values of the inductors are 1.5 H and 2.5 H. The total inductive reactance is _____.

An inductor is connected to a 120-V, 60-Hz supply. The current in the circuit is 2.4 A. What is the inductive reactance?

The symbol for reactive power of an inductor is _____.

An inductor with an inductance of three henrys (H) is to be connected to a 60 Hz circuit. What will the inductive reactance be?

In a pure inductive circuit, current _____.

Circuits are generally considered to contain _____ when any type of load that contains a coil is used.

An inductor is connected to a 240-V, 60-Hz supply. The current in the circuit is 5 A. What is the inductance of the inductor?

Two inductors are connected in parallel to a 120-V, 60-Hz supply. The values of the inductors are 1.5 H and 2.5 H. The total inductive reactance is _____.

An inductor has an inductive reactance of 64 Ω , and a wire resistance of 36 Ω . What is the impedance of the inductor?

When a magnetic field continually changes magnitude and direction, a voltage is continually being induced in the coil. This voltage is called _____ voltage.

The total current-limiting effect is called _____.

The amount of resistance compared with the inductive reactance determines the _____ of the coil.

The symbol for reactance is _____.

The symbol XL stands for _____.

Two inductors are connected in series to a 120-V, 60-Hz supply. The values of the inductors are 0.175 H and 0.255 H. The total circuit current is _____.

Volt-amperes-reactive is used to measure the _____ in a pure inductive circuit.

The symbol X_L stands for _____.