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PHYSICS DEPARTMENT
PHY 2005
Test 1
Name (print):
February 11, 2009
Signature:
On my honor, I have neither given nor received unauthorized aid on this examination.
YOUR TEST NUMBER IS THE 5-DIGIT NUMBER AT THE TOP OF EACH PAGE.
(1) Code your test number on your pink answer sheet (use 76–80 for the 5-digit number). Code your name on
your answer sheet. Darken circles completely. Code your UF ID number on your answer sheet.
(2) Print your name on this sheet and sign it also.
(3) You will receive one point for each correct answer and zero points for an incorrect answer or no answer.
(4) Use a number 2 pencil on the answer sheet. Do not make any stray marks, or the answer sheet may not be read properly.
(5) “X” is never the correct answer.
Useful Equations:
1 N = 1 kg m/ s2
1 J = 1 N m = 1 kg m2 / s2
1 W = 1 J/s
1 V = 1 J/ C
1 F = 1 C/ V
1 A = 1 C/ s
F~ = m~a
W = F~ · d~
K.E. =
k = 1/4π²0 = 9×109 N m2 / C2
²0 = 9×10−12 C2 / N· m2
e = 1.6×10−19 C
~
F~ = q E
P.E. = qV
F =
kq1 q2
r2
V = iR
q =VC
C = ²0 A/d
Ceff = C1 + C2 + C3
R = ρL/A
Reff = R1 + R2 + R3
1
mv 2
2
dW
= P = iV = i2 R = V 2 /R
dt
1
1
1
1
=
+
+
Ceff
C1
C2
C3
1
1
1
1
=
+
+
Reff
R1
R2
R3
1. On your pink answer sheet, did you correctly bubble in your test number in rows 76–80, and also bubble in your name
and your UF ID number (not your social security number!)? Also, did you print and sign your name at the top of your
test, and will you hand in the “white sheets?” before leaving the room? This question counts, and the correct answer
is “Yes”.
(1) Yes
(2) No
(3) X
(4) X
(5) X
2. In a demonstration involving the Van de Graaff generator, I got the generator running and then stood close to it. At
one point, I held a conducting, sharply pointed rod close to the Van de Graaff. Later I put my hand very close to the
Van de Graaff. Did a spark jump from the Van de Graaff either to the pointed, conducting rod or to my hand?
(1)
(2)
(3)
(4)
(5)
Hand sparked, but rod did not.
Rod sparked, but hand did not.
Both sparked.
Neither sparked.
Rod sparked, and I was smart enough not to put my hand near the Van de Graaff.
3. I have three different batteries on the front table. One is small and “boxy” and is sometimes used in a smoke alarm.
One is a standard “D” cell, which often appears in a flashlight. And one is a standard “AAA” cell, which I have in my
little portable radio. Which battery has the smallest Emf?
(1) AAA and D
(2) Boxy
(3) AAA
(4) AAA and Boxy
(5) They all have the same Emf?
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4. What is the large rectangular object on the front table?
(1) capacitor
(2) resistor
(3) battery
(4) ammeter
(5) It was never described in class.
5. Which of the following are appropriate units for the “resistivity” of some material?
(1) Ohm·meter
(2) meter
(3) Volt/meter2
(4) Ampere·meter
(5) Ohm/meter2
6. Two charges are separated by a distance r = 5 m. The magnitude of the force between these two charges is F = 4 N.
Then the charges are moved until the magnitude of F is 100 N. Now, how far apart are the charges?
(1) 1 m
(2) 0.2 m
(3) 1.25 m
(4) 0.25 m
(5) 0.5 m
7. Look at figure B on the figure sheet. Three identical capacitors of capacitance C = 2 F are in a circuit with a battery.
What is the effective capacitance of the three capacitors?
(1) 6 F
(2)
2
F
3
(3)
1
F
3
(4) 3 F
(5) 2 F
8. With the same situation in Figure B, the charge of the capacitor on the right is qc = 3 C. What is the Emf of the
battery?
(1) 1.5 V
(2) 6 V
(3) 3 V
(4) 4.5 V
(5) 7.5 V
9. Look at figure C on the figure sheet. Three identical resistors of resistance R = 2 Ω are in a circuit with a battery. What
is the effective resistance of the three resistors?
(1)
2
Ω
3
(2) 6 Ω
(3)
1
Ω
3
(4) 3 Ω
(5) 2 Ω
10. With the same situation in Figure C, the current flowing through Rc is ic = 3 A. What is the Emf of the battery?
(1) 6 V
(2) 1.5 V
(3) 3 V
(4) 4.5 V
(5) 7.5 V
11. A particular 1000 W space heater is designed to operate on 100 V. How much current flows through it when it is
operating?
(1) 10 A
(2) 3 A
(3) 30 A
(4)
2
A
15
(5) 1 A
(4)
2
Ω
15
(5) 1 Ω
12. What is the resistance of the same space heater when it is operating?
(1) 10 Ω
(2) 3 Ω
(3) 30 Ω
13. Two resistors are arranged in in a circuit with a battery as shown in Figure D. In this circuit, Ra = 2 Ω and Rb = 4 Ω.
The current flowing through Ra is ia = 8 A. How much current is flowing through Rb ?
(1) 4 A
(2) 8 A
(3) 3 A
(4) 6 A
(5) 5 A
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14. What is the Emf of the battery in this same figure?
(1) 16 V
(2) 32 V
(3) 12 V
(4) 24 V
(5) 10 V
15. Look at Figure A on the figure sheet. Three charges qa = 4 C, Q and qb = −1 C are lined up in row with a distance
of 1 m between qa and Q and also between Q and qb . The force on Q from qa has a magnitude of 8 N. What is the
magnitude of the total force on Q from both qa and qb ?
(1) 10 N
(2) 12 N
(3) 14 N
(4) 16 N
(5) 6 N
16. Look at Figure A on the figure sheet. Three charges qa = 4 C, Q and qb = −2 C are lined up in row with a distance
of 1 m between qa and Q and also between Q and qb . The force on Q from qa has a magnitude of 8 N. What is the
magnitude of the total force on Q from both qa and also qb ?
(1) 12 N
(2) 10 N
(3) 14 N
(4) 16 N
(5) 4 N
17. Look at Figure A on the figure sheet. Three charges qa = 4 C, Q and qb = −3 C are lined up in row with a distance
of 1 m between qa and Q and also between Q and qb . The force on Q from qa has a magnitude of 8 N. What is the
magnitude of the total force on Q from both qa and also qb ?
(1) 14 N
(2) 10 N
(3) 12 N
(4) 16 N
(5) 2 N
18. Look at Figure A on the figure sheet. Three charges qa = 4 C, Q and qb = −4 C are lined up in row with a distance
of 1 m between qa and Q and also between Q and qb . The force on Q from qa has a magnitude of 8 N. What is the
magnitude of the total force on Q from both qa and also qb ?
(1) 16 N
(2) 10 N
(3) 12 N
(4) 14 N
(5) 0 N
THE FOLLOWING QUESTIONS, NUMBERED IN THE ORDER OF THEIR APPEARANCE ON THE ABOVE
LIST, HAVE BEEN FLAGGED AS CONTINUATION QUESTIONS: 8 10 12 14 FOLLOWING GROUPS OF QUESTIONS
WILL BE SELECTED AS ONE GROUP FROM EACH TYPE
TYPE 1
Q# S 15
Q# S 16
Q# S 17
Q# S 18