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Unformatted text preview: 9000565 W%@UK\CC
(N6? \N NUDE/62} OLD DOMINION UNIVERSITY PHYSICS 227N/232N, Universiﬂ Physics I
Spring 2003
Second Examination 10:00 am  10:50 am
Wednesday 05 March 2003
Room 100, OCNPS
PROFESSOR: Dr. D. C. Cook Answer all 3 questions: Each question is worth different marks.
Full marks will only be given if complete working is shown. All questions should be answered on the examination paper.
If more space is required, attach sheets to paper. Text book may not be used.
This examination will be 15% of the total course assessment.
Honor Pledge Signature Candidate's Name SSN CONSTANTS AND E UATIONS :30=8.8510'12C2N'1m'2 1nC =10'9 C 111C =10'6 C
k =1/41t$o=9.0109Nm2C'2 Q=CV Fe=(kq1q2/r2) 1* V=IR E=(kq1/r2)l‘ P=VI U =kCI1CI2 /r R=pl/A V =kq2/r (DE = El E.dS = q/Eo 1 . CAPACITORS (3O Marks) A combination of resistors and capacitors connected in a circuit is shown in
Figure 1. The potential difference of 18.0V is placed across the combination to ground as shown. V=18.0V 6.00 9
WSﬁWV .6DOpF Capacsrw (I 3.00 (2 25.st 3.00“]: (£59616 “1%" Figure 1 When the switch S is OPEN calculate:
The potential difference (or voltage drop) between points a and b.
(10 marks) (a) ANSWER Calgary: has «he
Gummy: +0 Slot: WA
916::me cmwgc WV: USCG! f0 maiwimim
a (msmm alah‘m
bemmn CMW'm/ﬂ' (”loJO
and \Ioﬁnﬁe. 2. Capacitance (Total 32 Marks) 2(a) In words, explain what a capacitor is. Also explain the following.
When a piece of dielectric material is placed between the plates of a parallel
plate capacitor, its capacitance is found to increase. Explain how this change
comes about. (6 Marks) 2(b) What is the equivalent capacitance of each of the two circuits shown below. In
each circuit the capacitance values are C1: 9.6 pf C2: 7.6 pf. C3= 2.6 pf. (6+6=12 Marks) 0) ———l— ANSWER: Ctot = units = C
(ii) 2 C3
ANSWER. Ctot = Continued Page 6 2(c) (i) What is the equivalent capacitance of the combination shown in the ﬁgure
below (8 Marks) ANSWER F 10/,4ﬂ 100\/ “I 6 (2 LL/uﬂ
)1 2(0) (ii) What is the charge on each capacitor in the above Figure? (6 Marks)
ANSWERS: Q4 = C
Q5 = C
Q10 = _______ C Working for Q 2. End Q 2. 3. CIRCUIT ANALYSIS (Total 34 Marks)
The circuit shown in the ﬁgure below contains 4 resistors and two batteries whose
values are: R1=6Q, R2=3§2, R3=8§2, R4=4Q, El=6V, E2=12V. Calculate the current ﬂowing through each resistor. Figure 2 ANSWERS: OLD DOMINION UNIVERSITY PHYSICS 227N/232N, Universiﬂ Physics
Fall 2009 Second Examination 12:00lz45 pm Wednesday 21 October 2009
Room 142144, OCNPS
PROFESSOR: Dr. D. C. Cook FULL WORKING OR JUSTIFYING STATEMENTS ARE NEEDED TO OBTAIN FULL
MARKS. Make sure units are included with each answer. All questions must be answered on the examination paper.
Text book may not be used. This examination will be 12% of the total course assessment.
Honor Pledge Signature
Name UID CONSTANTS AND E UATIONS so = 8.8510'12 CZN" m2 1nC =10'9 c 1110 =10'6 C k =1/47tao=9.0109Nm2C'2 Q=CV F'= Eq Fe = (k qlqz/rz) 1‘ Circumference of Circle C= 21tr E = (k q] /r2) r Area of Circle A= 1tr2 U = k Q1q2 /r Surface area of a sphere AS = 4an V = k q; /r Volume of a sphere V= (4/3)*(TEI‘3) (DE = I E.dS = q/ao E = V/d K = 1/2 mv2 V = IR P = VI UE = qV R = pl/A Electronic Charge e = 1.60219 x 10"9 C Electron mass me = 9.109 x 10'3' kg
Proton mass mp = 1.672 x 10'27 kg 3. CIRCUIT ANALYSIS (Total 35 marks) In the circuit shown in Figure 2, calculate: (a) the current in the 3.00 9 resistor. (8 marks)
ANSWERS: Current =
(b) The unknown emf’s 81 and 82 (18 marks)
ANSWERS: 81 =
82 =
(c ) the unknown resistor R (9 marks)
ANSWERS: R = 6.00 9 $5.00 A Figure 2 2. OHM’S LAW and RESISTANCE (Total 35 Marks) 2(a) You apply a potential difference of 4.50 volts between the ends of a wire that is
2.50 m in length and 0.654 mm in radius. The resulting current through the wire is
17.6 A. What is the resistivity of the wire? Don’t forget the units. (15 marks) ANSWER
2(b) You are asked to wind a heater coil out of nichrome wire. Nichrome wire has a
resistance per unit length of 1.60 Q/m. The heater must have a power rating of 45 W
and is to be placed in series in a circuit with a 12 V battery. What length of nichrome
wire will you use? (20 marks) ANSWER m. When the switch S is CLOSED calculate:
(b) The potential difference between points b and ground.
(10 marks) ANSWER (c) How much charge ﬂows through the switch S when it is closed?
(10 marks) ANSWER ...
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 Spring '14
 ALEXANDERL.GODUNOV
 Physics

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