1. No category

PHY 111 College Physics II
Spring 2010
Exam 02 Review
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Two point charges, initially 2.0 cm apart, experience a 1.0-N force. If they are moved to a new
separation of 8.0 cm, what is the electric force between them?
A) 1/4 N
B) 2.0 N
C) 4.0 N
D) 16 N
E) 1/16 N
1)
2) Three point charges are located at the following positions: Q1 = 2.00 μC at x = 1.00 m; Q2 = 3.00 μC
at x = 0; Q3 = -5.00 μC at x = -1.00 m. What is the magnitude of the force on the 3.00-μC charge?
A) 5.40 × 10-2 N
B) 0.158 N
C) 8.10 × 10-2 N
D) 0.189 N
E) 0.135 N
2)
3) A point charge Q = 7.00 × 10-9 C is placed at the origin of an x-y coordinate system. What is the
electric field intensity E at a distance of x = 30 cm from this charge? (Use k = 9 × 109 Nm 2/C2.)
3)
A) 500 N/C
B) 100 N/C
C) 700 N/C
D) 400 N/C
E) 600 N/C
4) A metal sphere of radius 2.0 cm carries a charge of 3.0 μC. What is the electric field 6.0 cm from the
center of the sphere?
A) 4.2 × 106 N/C
B) 9.3 × 106 N/C
C) 6.4 × 106 N/C
D) 5.7 × 106 N/C
E) 7.5 × 106 N/C
4)
5) A proton is placed in an electric field of intensity 700 N/C. What is the magnitude and direction of
the acceleration of this proton due to this field?
A) 6.71 × 1010 m/s2 opposite to the electric field
5)
B) 6.71 × 1010 m/s2 in the direction of the electric field
C) 6.71 × 109 m/s2 opposite to the electric field
D) 67.1 × 1010 m/s2 in the direction of the electric field
E) 67.1 × 1010 m/s2 opposite to the electric field
1
6) An 800 V/m electric field is directed along the +x-axis. If the potential at x = 0 m is 2000 V, what is
the potential at x = 2 m?
A) 1000 V
B) 400 V
C) 600 V
D) 200 V
E) 800 V
6)
7) Three charges are placed as follows along the x- and y-axes of an xy-coordinate system: q1 = 2.00
7)
μC at x 1 = 0 m, q2 = 4.00 μC at x 2 = 3.00 m, and q3 = 6.00 μC at y = 4.00 m. What is the electric
potential energy of this system of charges?
A) -90.0 mJ
B) -94.2 mJ
C) 0 J
D) 94.2 mJ
E) 90.0 mJ
8) A 4.0-μC charge is situated at the origin of an xy-coordinate system. What is the potential
difference between the points x = 4.0 m and y = 2.0 m because of this charge?
A) 0 V
B) -9.0 × 103 V
8)
C) -36 × 103 V
D) 9.0 × 103 V
E) 36 × 103 V
Figure 20-9
9) Two point charges of magnitude +4.00 μC and +2.00 μC are placed at the opposite corners of a
rectangle as shown in Figure 20-9. What is the potential difference between points A and B?
A) -203 × 103 V
B) -22.5 × 103 V
C) +22.5 × 103 V
D) 0 V
E) +203 × 103 V
2
9)
10) The potential difference between the plates of a parallel plate capacitor is 35 V and the electric field
between the plates has a strength of 750 V/m. If the plate area is 4.0 × 10-2 m 2, what is the
10)
capacitance of this capacitor?
A) 7.6 × 10-14 F
B) 7.6 × 10-12 F
C) 7.6 × 10-10 F
D) 7.6 × 10-11 F
E) None of the other choices is correct.
11) A 6.00-μF parallel plate capacitor has a charge of +40.0 μC and -40.0 μC on each plate, respectively.
The potential energy stored in this capacitor is:
A) 123 μJ
B) 133 μJ
C) 143 μJ
D) 113 μJ
E) 103 μJ
11)
12) The resistance of a 100-cm wire of cross sectional area 2 × 10-6 m 2 is 400 Ω. What is the resistivity
of the material of this wire?
A) 8 × 10-4 Ωm
12)
B) 8 × 10-6 Ωm
C) 0.8 × 10-6 Ωm
D) 0.8 × 10-4 Ωm
E) 0.8 × 10-5 Ωm
13) The power rating of a 400 Ω resistor is 0.25 W. What is the maximum voltage?
A) 40 V
B) 30 V
C) 20 V
D) 10 V
E) 50 V
3
13)
Figure 21-3
14) A 4-Ω resistor is connected in parallel with a 12-Ω resistor and this combination is connected to a
DC power supply with voltage V as shown in Figure 21-3. If the total current in this circuit is 2 A,
what is the value of voltage V?
A) 1.5 V
B) 2 V
C) 3 V
D) 6 V
E) None of the other answers is correct.
14)
Figure 21-7
15) Three 2.0-Ω resistors are connected across the sides of an equilateral triangle ABC as shown in
Figure 21-7. What is the equivalent resistance between any two points, AB, BC, or AC, of this
circuit?
A) 3.3 Ω
B) 6.0 Ω
C) 1.3 Ω
D) 4.3 Ω
E) 2.0 Ω
4
15)
Figure 21-14
16) A number of resistors are connected across points A and B as shown in Figure 21-14. What is the
equivalent resistance between points A and B?
A) 6 Ω
B) 12 Ω
C) 8 Ω
D) 10 Ω
E) 4 Ω
16)
17) A 2.0 μF and a 4.0 μF capacitor are connected in series across an 8.0-V DC source. What is the
charge on the 2.0 μF capacitor?
A) 11 μC
B) 4.0 μC
C) 2.0 μC
D) 12 μC
E) 25 μC
17)
18) A 8.0 μF capacitor is connected in series with a 6.0 kΩ resistor across a 20-V DC source and a
switch. What is the time constant of this RC circuit?
A) 12 ms
B) 18 ms
C) 9.0 ms
D) 48 ms
E) 40 ms
18)
5
Answer Key
Testname: PHY111S10REV02
1) E
2) D
3) C
4) E
5) B
6) B
7) D
8) B
9) B
10) B
11) B
12) A
13) D
14) D
15) C
16) C
17) A
18) D
6