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Practice MC Questions for Charge and Circuit Test AP 2
2015 Davis
Answers are on my website
1.
An aluminum nail has an excess charge of +3.2 x 10-6 C. How many electrons
must be added to the nail to make it electrically neutral?
A)
2.0 x 1013
B)
2.0 x 1019
C)
3.2 x 10-6
D)
3.2 x 106
E)
5.0 x 10-14
2.
Two point charges are arranged along the x axis as shown in the figure. At which
of the following values of x is the electric potential equal to zero?
Note: At infinity, the electric potential is zero.
A. +0.05 m
B.+0.29 m
C. +0.40 m
D. +0.54 m
E. +0.71 m
3.
Which one of the following statements is true concerning the magnitude of the
electric field at a point in space?
A)
It is a measure of the total charge on the object.
B)
It is a measure of the electric force on any charged object.
C)
It is a measure of the ratio of the charge on an object to its mass.
D)
It is a measure of the electric force per unit mass on a test charge.
E)
It is a measure of the electric force per unit charge on a test charge.
4.
What is the magnitude and direction of the electric force on a -1.2 µC charge at a
point where the electric field is 2500 N/C and is directed along the +y axis.
A)
0.15 N, -y direction
B)
0.15 N, +y direction
C)
0.0030 N, -y direction
D)
0.0030 N, +y direction
E)
4.3 N, +x direction
5.
The electric potential at a certain point is space is 12 V. What is the electric
potential energy (the work value) of a -3.0 μC charge placed at that point?
A)
+4 μJ
B)
-4 μJ
C)
+36 μJ
D)
-36 μJ
E)
zero µJ
6.
How many electrons flow through a battery that delivers a current of 3.0 A for
12 s?
A)
4
B)
36
C)
4.8 x1015
D)
6.4 x 1018
E)
2.2 x 1020
7.
The potential difference across the ends of a wire is doubled in magnitude. If
Ohm's law is obeyed, which one of the following statements concerning the resistance of
the wire is true?
A)
The resistance is one half of its original value.
B)
The resistance is twice its original value.
C)
The resistance is not changed.
D)
The resistance increases by a factor of four.
E)
The resistance decreases by a factor of four.
8.
Three point charges Q, Q, and +3Q are arranged along a line as shown in the
sketch.
What is the electric potential at the point P?
A. +kQ/R
B. 2kQ/R
C. 1.6kQ/R
D. +1.6kQ/R
E. +4.4kQ/R
9. A 5-A current is maintained in a simple circuit that consists of a resistor between the
terminals of an ideal battery. If the battery supplies energy at a rate of 20 W, how large is
the resistance?
A) 0.4 Ω
B) 0.8 Ω
C) 2 Ω
D) 4 Ω
E) 8 Ω
10. Two 15-W and three 25-W light bulbs and a 24 V battery are connected in a series
circuit. What is the current that passes through each bulb?
A) 0.23 A
B) 0.51 A
C) 0.96 A
D) 1.6 A
E) 4.38 A
11. Complete the following statement: A simple series circuit contains a resistance R and
an ideal battery. If a second resistor is connected in parallel with R,
A) the voltage across R will decrease.
B) the current through R will decrease.
C) the total current through the battery will increase.
D) the rate of energy dissipation in R will increase.
E) the equivalent resistance of the circuit will increase.
12. Three resistors are connected as shown in the figure. The potential difference
between points A and B is 26 V.
How much current flows through the 3- resistor?
A. 2.0 A
B. 4.0 A
C. 6.0 A
D. 8.7 A
E. 10.0 A
13. Three identical point charges, Q, are placed at the vertices of an equilateral triangle as
shown in the figure. The length of each side of the triangle is d. Determine the magnitude
and direction of the total electrostatic force on the charge at the top of the triangle.
A.
B.
C.
D.
E. zero
14.
Four point charges are placed at the corners of a square as shown in the figure.
Each side of the square has length 2.0 m. Determine the magnitude of the electric field at
the point P, the center of the square.
A. 2.0  106 N/C
B. 3.0  106 N/C
C. 9.0  103 N/C
D. 1.8  104 N/C
E. 2.7  104 N/C
15.Some light bulbs are connected in parallel to a 120 V source as shown in the
figure. Each bulb dissipates an average power of 60 W. The circuit has a fuse F that
burns out when the current in the circuit exceeds 9 A. Determine the largest number
of bulbs, which can be used in this circuit without burning out the fuse.
( Hint, find the R of each bulb from P=V2/R, then find the max total R you can
have to get I=9A. Last, find out how many bulbs that is in parallel.)
A. 9
B.18
C. 25
D. 34
E. 36
16.
Determine the length of a copper wire that has a resistance of 0.172 Ω and a
cross-sectional area of 1 x 10-4 m2. The resistivity of copper is 1.72 x 10-8 Ω • m.
A)
0.1 m
B)
10 m
C)
100 m
D)
1000 m
E)
10 000 m
17.
Which one of the following statements is true concerning capacitors of unequal
capacitance connected in series?
A)
Each capacitor holds a different amount of charge.
B)
The equivalent capacitance of the circuit is the sum of the individual
capacitances.
C)
The total voltage supplied by the battery is the sum of the voltages across
each capacitor.
D)
The total positive charge in the circuit is the sum of the positive charges
on each capacitor.
E)
The total voltage supplied by the battery is equal to the average voltage
across all the capacitors.
18. Five resistors are connected as shown. What is the equivalent resistance between
points A and B?
A. 6.8 
B. 9.2 
C. 3.4 
D. 2.1 
E. 16 
19.
Three parallel plate capacitors, each having a capacitance of 1.0 µF are connected
in parallel. The potential difference across the combination is 100 V. What is the charge
on any one of the capacitors?
A)
30 µC
B)
100 µC
C)
300 µC
D)
1000 µC
E)
3000 µC
20.
Two wires A and B are made of the same material and have the same diameter.
Wire A is twice as long as wire B. If each wire has the same potential difference across
its ends, which one of the following statements is true concerning the current in wire A?
A)
The current is one-fourth that in B.
B)
The current is four times that in B.
C)
The current is equal to the current in B.
D)
The current is half as much as that in B.
E)
It is twice as much as that in B.
21. A 3.0-µF capacitor is connected in series with a 4.0-µF capacitor and a 48-V battery.
What quantity of charge is supplied by the battery to charge the capacitors?
A)
3.4 x 10-4 C
B)
7.3 x 10-4 C
C)
3.0 x 10-5 C
D)
8.2 x 10-5 C
E)
1.8 x 10-6 C
22.
What is the equivalent capacitance of the combination of capacitors shown in the
circuit?
A. 0.37 µF
B. 3.3 µF
C. 4.6 µF
D. 0.67 µF
E. 2.1 µF
23. When two capacitors are connected in series, the equivalent capacitance of the
combination is 120 µF. When the two are connected in parallel, however, the equivalent
capacitance is 480 µF. What are the capacitances of the individual capacitors?
A) 240 µF and 240 µF
B) 125 µF and 325 µF
C) 175 µF and 275 µF
D) 150 µF and 300 µF
E) 80 µF and 370 µF
24. The magnitude of the charge on the plates of an isolated parallel plate capacitor is
doubled. Which one of the following statements is true concerning the capacitance of
this parallel-plate system?
A) The capacitance is decreased to one half of its original value.
B) The capacitance is increased to twice its original value.
C) The capacitance remains unchanged.
D) The capacitance depends on the electric field between the plates.
E) The capacitance depends on the potential difference across the plates.
25. Which one of the following changes will necessarily increase the capacitance of a
capacitor?
A) decreasing the charge on the plates
B) increasing the charge on the plates
C) placing a dielectric material other than air or a vacuum between the plates
D) increasing the potential difference between the plates
E) decreasing the potential difference between the plates