Question 1

Volt-amperes-reactive is used to measure the in a pure inductive circuit.&#10;A) watts&#10;B) reactive power&#10;C) volt amperes&#10;D) joules

Accepted Answer

In a pure inductive circuit, the power is reactive, which means it oscillates back and forth between the source and load without being converted to useful work. Therefore, the best choice to measure it is in volt-amperes-reactive (VAR).

Question 2

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?&#10;A) .0048 H&#10;B) .0075 H&#10;C) .1185 H&#10;D) .127 H

Accepted Answer

D

Question 3

In a pure inductive circuit, current .&#10;A) lags voltage by 90&#176;&#10;B) leads voltage by 90&#176;&#10;C) is in phase with voltage&#10;D) lags voltage by 180&#176;

Accepted Answer

In a pure inductive circuit, the current lags the voltage by 90°. This is because the inductor resists changes in current and therefore initially opposes the flow of current when the voltage is applied. As the current builds up, the inductor's magnetic field also builds up and eventually reaches maximum strength. At this point, the inductor no longer opposes the flow of current and the current reaches its maximum value, which is 90° out of phase with the voltage.

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 .&#10;A) 3.54 A&#10;B) 4.84 A&#10;C) 5.41 A&#10;D) 6.12 A

Accepted Answer

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

Question 5

The symbol XL stands for _.&#10;A) resistance&#10;B) inductive resistance&#10;C) inductive reactance&#10;D) resistive reactance

Accepted Answer

XL stands for inductive reactance, which is the opposition to the change of current by an inductor in an AC circuit.

Question 6

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 .&#10;A) 0.74 A&#10;B) 1.02 A&#10;C) 1.85 A&#10;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 7

The current-limiting property of an inductor is called .&#10;A) resistance&#10;B) inductance&#10;C) reactance&#10;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 8

Circuits are generally considered to contain when any type of load that contains a coil is used.&#10;A) inductance&#10;B) reactance&#10;C) resistance&#10;D) volt-amperes

Accepted Answer

When a load containing a coil (such as a motor or transformer) is used in a circuit, it introduces inductance, which is the property of a circuit or component that opposes changes in current flow. This inductance is typically measured in units of Henries and can be represented by a symbol L in circuit diagrams.

Question 9

The amount of resistance compared with the inductive reactance determines the of the coil.&#10;A) power factor (PF)&#10;B) quality (Q)&#10;C) phase angle (&#952;)&#10;D) reactance (X)

Accepted Answer

The quality factor (Q) of a coil is determined by the ratio of its inductive reactance to its resistance (Q = X/R). Therefore, the amount of resistance compared with the inductive reactance determines the quality factor of the coil.

Question 10

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 .&#10;A) 525.5 &#937;&#10;B) 533.49 &#937;&#10;C) 942.5 &#937;&#10;D) 1508 &#937;

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 11

The symbol for reactive power of an inductor is .&#10;A) W&#10;B) VA&#10;C) VARs&#10;D) P

Accepted Answer

The answer of The symbol for reactive power of an...

Question 12

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?&#10;A) 57.08 &#937;&#10;B) 104.8 &#937;&#10;C) 288 &#937;&#10;D) 904.8 &#937;

Accepted Answer

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

Question 13

The symbol for reactance is .&#10;A) RL&#10;B) XL&#10;C) L&#10;D) H

Accepted Answer

The answer of The symbol for reactance is .&#10;A) RL&#10;B)...

Question 14

An inductor with an inductance of three henrys (H) is to be connected to a 60 Hz circuit. What will the inductive reactance be?&#10;A) 180 &#937;&#10;B) 360 &#937;&#10;C) 565 &#937;&#10;D) 1131 &#937;

Accepted Answer

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

Question 15

An inductor is connected to a 60 Hz circuit. The inductive reactance is 75.4 &#937;. What is the inductance of the inductor?&#10;A) 0.2 H&#10;B) 5 H&#10;C) 284 H&#10;D) 4524 H

Accepted Answer

The answer of An inductor is connected to a 60...

Question 16

The unit of inductance is the .&#10;A) reactance&#10;B) henry&#10;C) ohm&#10;D) hertz

Accepted Answer

The answer of The unit of inductance is the .&#10;A)...

Question 17

An inductor has an inductive reactance of 64 &#937;, and a wire resistance of 36 &#937;. What is the impedance of the inductor?&#10;A) 10 &#937;&#10;B) 28 &#937;&#10;C) 73.4 &#937;&#10;D) 82.92 &#937;

Accepted Answer

The answer of An inductor has an inductive reactance of...

Question 18

The total current-limiting effect is called .&#10;A) reluctance&#10;B) impedance&#10;C) resistive reactance&#10;D) inductive resistance

Accepted Answer

The answer of The total current-limiting effect is called .&#10;A)...

Question 19

When a magnetic field continually changes magnitude and direction, a voltage is continually being induced in the coil. This voltage is called voltage.&#10;A) conducted&#10;B) induced&#10;C) applied&#10;D) inductive

Accepted Answer

The answer of When a magnetic field continually changes magnitude...

Question 20

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 .&#10;A) 42.5 &#937;&#10;B) 365.5 &#937;&#10;C) 553.44 &#937;&#10;D) 1508 &#937;

Accepted Answer

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

Question 21

An inductor has an inductive reactance of 12 &#937;, and a wire resistance of 16 &#937;. What is the impedance of the inductor?&#10;A) 4 &#937;&#10;B) 20 &#937;&#10;C) 28 &#937;&#10;D) 400 &#937;

Accepted Answer

The answer of An inductor has an inductive reactance of...

Deck 17: Inductance in Alternating Current Circuits