Abington Heights High School
Physics
Practice Quiz Chapter 21 - Quiz 2
1.
The graph shows the voltage across and the current through a single circuit element connected to an ac generator.
R-1 Ref 23-1

Identify the circuit element.
A.The element is a 25-W resistor.
B.The element is a 35-W resistor.
C.The element is a 0.45-H inductor.
D.The element is a 360-µF capacitor.
E.The element is a 510-µF capacitor.

2. When the frequency of an ac circuit is decreased, the current in the circuit increases. Which combination of elements is most likely to comprise the circuit?
A.resistors only
B.inductors only
C.capacitors only
D.capacitors and resistors
E.inductors and capacitors
3. Which circuit elements act to oppose changes in the current in an ac circuit?
A.resistors only
B.capacitors only
C.inductors only
D.both resistors and inductors
E.both capacitors and resistors
4. Which one of the following graphs shows how the inductive reactance varies with frequency?


Answer:
5.

A variable inductor is connected to an ac source. What effect does increasing the inductance have on the reactance and current in this circuit?


Reactance

Current


A.


no change

no change


B.


decreases

no change


C.


increases

increases


D.


decreases

increases


E.


increases

decreases


6. An ac voltage source that has a frequency f is connected across the ends of an inductor. Which one of the following statements correctly indicates the effect on the inductive reactance when the frequency is increased to 2f?
A.The inductive reactance increases by a factor of two.
B.The inductive reactance increases by a factor of four.
C.The inductive reactance is unchanged.
D.The inductive reactance decreases by a factor of four.
E.The inductive reactance decreases by a factor of two.
7. Two 0.18-H inductors and one 0.36-H inductor are connected in series across the terminals of a 50.0-Hz ac generator. What is the total inductive reactance of this circuit?
A.230 W
B.112 W
C.88 W
D.56 W
E.27 W
8. In an ac circuit, a 0.025-H inductor is connected to a generator that has an rms voltage of 25 V and operates at 50.0 Hz. What is the rms current through the inductor?
A.0.62 A
B.2.0 A
C.3.2 A
D.7.1 A
E.14 A
9. Which one of the following phasor models correctly represents a circuit comprised of only an inductor and an ac generator?


Answer:
10.
The voltage across and the current through a single circuit element connected to an ac generator is shown in the graph.
R-2 Ref 23-2

Which one of the following statements concerning this circuit element is true?
A.The element is a resistor.
B.The element is a capacitor.
C.The element is an inductor.
D.The element could be a resistor or an inductor.
E.The element could be an inductor or a capacitor.

11.
The voltage across and the current through a single circuit element connected to an ac generator is shown in the graph.
R-2 Ref 23-2

At what frequency do charges oscillate in this circuit?
A.0.01 Hz
B.0.04 Hz
C.0.09 Hz
D.11 Hz
E.25 Hz

12.
The voltage across and the current through a single circuit element connected to an ac generator is shown in the graph.
R-2 Ref 23-2

Determine the rms current through this circuit element.
A.1.0 A
B.1.4 A
C.2.0 A
D.2.8 A
E.4.0 A

13.
The voltage across and the current through a single circuit element connected to an ac generator is shown in the graph.
R-2 Ref 23-2

Determine the reactance of this circuit element.
A.20 W
B.25 W
C.40 W
D.57 W
E.80 W

14. Which one of the following statements concerning an ac circuit is true?
A.The current and voltage are in phase for a capacitor in an ac circuit.
B.On average the power dissipated by a resistor in an ac circuit is zero.
C.The current and voltage are 90° out of phase for a resistor in an ac circuit.
D.Inductors in an ac circuit offer little opposition to current at high frequencies.
E.When only resistance is present in an ac circuit, voltage and current are in phase.
15. Note the following circuit elements: (1) resistors, (2) capacitors, and (3) inductors.
Which of these elements uses no energy, on average, in an ac circuit?
A.1 only
B.2 only
C.3 only
D.both 2 and 3
E.both 1 and 3

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