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Instructor(s): Nakayama/Barrow
PHY 2005
Name (print, last first):
PHYSICS DEPARTMENT
Exam 1
Signature:
On my honor, I have neither given nor received unauthorized aid on this examination.
June 7, 2010
YOUR TEST NUMBER IS THE 5-DIGIT NUMBER AT THE TOP OF EACH PAGE.
(1) Code your test number on your answer sheet (use lines 76–80 on the answer sheet for the 5-digit number) .
Code your name on your answer sheet.
DARKEN CIRCLES COMPLETELY . Code your UFID number on your answer sheet.
(2) Print your name on this sheet and sign it also.
(3) Do all scratch work anywhere on this exam that you like.
Circle your answers on the test form.
At the end of the test, this exam printout is to be turned in. No credit will be given without both answer sheet and printout.
(4) Blacken the circle of your intended answer completely, using a #2 pencil or blue or black ink . Do not make any stray marks or some answers may be counted as incorrect.
(5) The answers are rounded off. Choose the closest to exact. There is no penalty for guessing.
(6) Hand in the answer sheet separately.
Physical Constants: g = 9 .
8 m/s 2 m e
= 9 .
11 × 10 − 31 Kg m p
= 1 .
67 × 10 − 27 Kg e = 1 .
6 × 10 constant k in Coulomb’s Law: k = 9 × 10 9
− 19 C
Nm 2 /C 2
µ o
= 4 π × 10 − 7 N/A 2 ε o
= 8 .
85 × 10 − 12 C 2 /Nm 2
1. Two identical metal spheres initially carry charges of 2 .
0 µ C and − 10 µ C; the electric force between the spheres is
5 .
0 × 10 − 4 N. The spheres are touched and again separated to the initial distance. The electric force between them is now:
(1) repulsive 4 .
0 × 10 − 4 N (2) attractive 4 .
0 × 10 − 4 N (3) repulsive 6 .
3 × 10 − 4 N (4) attractive 4 .
3 × 10 − 4 N (5) zero
2. Two charges are placed on an x axis. One is − 8 .
0 µ C and at x = 0. The other is 2 .
0 µ C and at x = 2 .
0 m. Where is the electric field due to these charges zero? (in m)
(1) x = 4 .
0 (2) x = − 2 .
0 (3) x = 0 .
67 (4) x = 1 .
3 (5) Nowhere on the x axis
3. A positively charged 5.0-g ball hangs as a pendulum from a very thin thread.
It hangs at an angle of 15 ◦ when placed in a horizontal field of 2 .
0 × 10 4
What is the charge on the ball?
N/C.
(1) 6 .
56 × 10 − 7
(2) 8 .
86 × 10 − 8
(3) 3 .
28 × 10 − 7
(4) 1 .
58 × 10 − 6
(5) 5 .
22 × 10 − 6
C
C
C
C
C
4. Two large parallel metal plates are 0.30 cm apart. One is connected to the positive side of a 12 V battery while the other is connected to the negative side. With the battery still connected, the plates are moved to a separation of 0.60 cm.
What is the potential difference across the capacitor now?
(1) 12 V (2) 24 V (3) 48 V (4) 6 V (5) 3 V

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5. In the figure,
E
2 incorrectly .
R
1
= 6 V and E
3
= 2 Ω, R
2
= 4 Ω, R
3
= 3 Ω, R
4
= 4 Ω, R
5
= 2 Ω, E
1
= 5 V,
= 3 V . Choose one equation which describes the circuit
(1) 9 = 4 I
2
(2) 8 = 6 I
1
(3) 3 = − 4 I
2
(4) 11 = 6 I
1
(5) I
2
+ I
3
+ 5 I
3
+ 4 I
2
+ 5
+ 5
= I
1
I
I
3
3
6. Which of the following are appropriate units for the permittivity of free space?
(1) F/m (2) Nm 2 /C 2 (3) Ωm (4) Ampere-hour
7. In the figure, r = 1 .
0 Ω and R = 2 .
0 Ω. Resistor R generates 30 J of heat in
1 minute. What is the value of E ?
(5) eV
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(1) 1.5 V (2) 12 V (3) 0.8 V (4) 45 V
8. There are four charges arranged at the corners of a square as shown in the figure. In which quadrant is the net force exerted on the charge at the origin?
(1) 4th quadrant
(2) 2nd quadrant
(3) 3rd quadrant
(4) 1st quadrant
(5) not enough information
(5) 0.1 V
9. A proton accelerates from rest as it falls through a potential difference. If the proton acquires a speed of 5 × 10 6 how large a potential difference did it fall? (in V) m/s,
(1) 1 .
3 × 10 5 (2) 2 .
6 × 10 5 (3) 1 .
3 × 10 5 (4) 7 .
1 × 10 1 (5) 5 .
5 × 10 4
10. The current through a certain light bulb is 4.0 A. How many electrons flow through the bulb each second?
(1) 2 .
5 × 10 19 (2) 2.0
(3) 2 .
1 × 10 30 (4) 2 .
4 × 10 27 (5) 6 .
4 × 10 − 19
11. In the figure, C
1
= 3 µ F, C
2
= 6 µ F and C
3
= 12 µ F. What is the equivalent capacitance between points A and B ? (in µ F)
(1) 7.0
(2) 2.6
(3) 21 (4) 2.0
(5) 1.7

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12. In a demonstration, a wire, which consists of copper portion and nichrome portion, was stretched over the front table.
When I applied a voltage of 120 V to the wire, the nichrome portion glowed red hot and it burned a piece of paper hanging on it, whereas nothing happened to a piece of paper on the copper portion. This is because
(1) nichrome has larger resistivity than copper.
(2) copper has larger resistivity than nichrome.
(3) more current flows through the nichrome portion than that through the copper portion.
(4) more current flows through the copper portion than that through the nichrome portion.
(5) the potential drop across the copper portion is larger than that across the nichrome portion.
13. In the figure, R
1
= 4 Ω, R
2
= 6 Ω and R resistance between points A and B ? (in Ω)
3
= 5 Ω.
What is the equivalent
(1) 7.40
(2) 2.25
(3) 15.0
(4) 1.62
(5) 5.00
14. House circuits are wired in:
(1) parallel (2) series (3) both series and parallel (4) neither series nor parallel (5) It depends.
15. In the figure, R
1
= 2 Ω, the capacitor? (in C)
R
2
= 5 Ω, R
3
= 4 Ω, R
4
= 3 Ω, R
5
= 5 Ω, C = 2 µ F and E = 20 V . The circuit is in the steady state. What is the charge stored in
(1) 4 .
0 × 10 − 6
(2) 2 .
0 × 10 − 6
(3) 1 .
0 × 10 − 5
(4) 8 .
0 × 10 − 6
(5) 2 .
0 × 10 − 5