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.4 _ PHYS 222 EXAM #1 Spring Semester 2007 ABC Name:
Covering Chapters 21, 22, 23 & 24 Instructions: Circle the letter corresponding to the corre answer. If you are sure that your answer is correct and it does not
match any of those given, then write your answer on the blank space in F [6] Problem #1. The ﬁgure shows three situations (i), (ii), and (iii) involving three charged spherical conducting shells of
different radius, and three point charges. Rank the situations according to the force on the point charges. (i.e., The situation where
the force on the point charge qo is greatest should be listed ﬁrst, and the situation where the force on qbis smallest should be listed last.) Answer: A. (i), (ii), (iii). 9
Th. (iii), (ii), (i). aﬁii),
F. (iii), (i). c. (i), (iii), (ii). 
(i), (ii).  .............................................. . For Problems #2, and #3, use the figure at the right.
Two point charges Q, = 9.60 uC and Q; = +5.80 uC, are ~
separated by a distance of 48.2 cm, and located on the ‘
line as shown at the right. [8] Problem #2. Determine the force (magnitude and direction) on Q1 d to Q2 ? ’
Answer: A. 9.9 x 101 N toward Q2. B. 2.2 x 10° N toward Q2. . 1.4 x 10° N toward Q2. 7 D. 6.1x101Ntoward Q. E. 1.5x101Nawayﬁ'osz. 2J5 x/O'A/ 1590on Oz. ’———.Problem #3. } on .it due to Q. and Answer: 24
D. 2.5m the charge Q; = 3.70 HC is to be placed on the line joining the two charges so that the net force
s zero. . Gii/e the location of Q; with respect to Q1. . to the right of Q,. B. 221m tothe left of Q1 . ' C. 3.2 m to the right of Q1 fQ,. E. 2.2mto t11erighton,. F. 1.24m tn ~qu right at Q, roblem #4. An electron and a proton are separated by distance of 7.70 x 10‘9m to form an electric dipole. The di ole
ment vector has magnitude and points fro the AP
Answer: A. 6.1 X,.lO'28 C.m, electron, proton. . @
electron, proton. (1),.)12 x 10'27 C.m, electron, proton.
F. to the . . ’07?
C.m, electron, proton. C. 9.6 x 10‘27 C.m,
. 3.2 x 10'29 C.m, electron, proton. [7]Problem #5. The sketch below shows some lines representing a section of an electrical tie] and three dashed boxes.
‘V (i) Mark an ”X in the dashed oox which has the weakest electric ﬁeld. ’
'l/(ii) Mark a "Y" in the dashed box which has the strongest electric ﬁeld. (iii) For each of boxes Land 3 accurately sketch two lines representing
X equipotential lines for the electric ﬁeld in that box. #roblem #6. M, Z, Q and R represent atomic uclei. Complete the nuclear reaction 74M + ‘Z —> 52Q + (x + Y)R by giving
I e number of protons X and the number of neu ns Y. (Use the following information M(37 protons, 37 neutrons), Z(2protons, 2neutrons), Q(30 protons, 22 neutrw .). .
—17. C.X=l9,Y=17. D.X=17,Y=10. @ngqnw Answers: A. X=10,Y=8.
E.X=29,Y=37. F.X= = a For Problems #7 and #8 use the ﬁgure at the right. Q; a .........
Point charges Q1 and Q; are located at two vertices of an equilateral triangle. Point P is the third vertex. The length of each side of the triangle is 16.0 cm. Q, = +8.50 ”C, and Q; = 4.6011 . W a. ,t. 31. . t . .
' V’ 411?» 1' 4" ,
\‘roblem #9. Po' '
'1, Q2 and Q3 1 . 1
B. 1.9 x 10° J. g 4.9 x 10° J. D. 7.9 x 10 J. E. .4.0 go J. 1c potentla at point P is . (Assume V = 0 at inﬁnity.)
V ,
Q3 = +7.90 W potential energy of the conﬁguration formed
Answers: é >32 x . . ’
F. ——————— E, 547500,; 3: .‘ 45X/05 26 I 4'77/4X I05
,0, : /. we (a ,0. : ~/. ax/W [93 : /.atox10 *0 . 5.1x10“v. B. 5.9x105v. c. 9.9x105v. D.7.1x104V. E. 1.9x105v.
=Oatinﬁnity.)
b") awe. Uz=~’0.’5’¢’ as 06w HY S 222 EXAM #1 Fall Semester 2006 ABC Name: : roblem #10. The electric potential in a region of space is given by V (6. 70 V/m2)x2 — (5. 40V/m3 )y3 + (3. 90 V/m)z.
' termine the electric ﬁeld in the form E = Exi + Eyj + Ezk‘ ' 2.0 in, 2.0'm, l.0 m). Answers: A. E = (3.1 V/m)i + (38 V/m)j  (1.7 V/m)k. (27 [Oi + (65 I0]  (3.9 V)k. C. E =(—14 V/m)i + (50 V/m)j  (8.2 V/m)k. D. E = (18 / + (83 V/m)j (2.5 V/m)k. E. .E = (7.0 V/m)i + (50 V/m)j + (8.2 V/m)k. F. For Problem #11, #12 and #13 use the ﬁgure at the right.
The ﬁgure represents a solid sphere, with radius 6. 00 cm, concentric with a spherical shell of radius 12.0 cm. The solid sphere has a
charge of —8.70 11C on it, and the outer shell has a net charge
of +5.40 11C on it. , 4.....»— roblem #11. The surface charge density on the solid sphere lS
swer: 'A. —1.0 x104C/m. B. —1. 5 x104C/m. . c. —1.9x 104cm. ..—2 8 x104C/m.
E. 1.2x10‘4C/m. F. ~ 7. 7x70 4cm 9— T 1: 0.0115 WProblem #12. In order to use Gauss’s Law to c ulate the electric ﬁeld at a point 10.0 cm from the center, the shape of the
aussian surface to use is a Answer: A. cylinder. B. circle.
t 10.0 cm from the center is E . D. square. E. line. F.
\mroblem #13. The magnitude and direction of the electric ﬁe _
er: A. 5.9 x 106 V/m, radially inward. $1 x 106 ,radially outward. C. 7.5 x l06 V/m, radially inward. QM D. 1. 8 x106 V/m, radially outward 7. x V/m, radially inward. F.  roblem #14. Determine the net electric ﬂux through the ql _,’.—q; . .qs 3 _
m . . . , .1 ¢ v w. e shown by the broken lme at the rlght. , ............. ,
' q; =2. 0e, q; =+4. 0e, q3= 6. 0e, 7’28“ 5 _." ’3' q.. £9
q4=8. 0e andq5= +7. 0e. ”I ”Q' 7 ._‘ .(h ”a" .
/ Z7 e, 7 ~ ........... Answers: A. +1.4x10‘7N.m2/ B. —3.4x10'sN.m/C c. —5.4x10'8 N.m2/C +9.1x10'8N.m2/C
1.lx10 7N.m2/C. F. —3.1 v'o‘7,\'1Mz/C roblem # 15. 7. 90 . . .
much  : e 15 enclosed 1n a region that 15 3. 00 cm ﬁom the center 0 :¢._71.1x10‘:67C. B. 27.x10‘sc C..37x10‘8
l7 XIDY 1 n
@mblem #15. A charge of Q= 6e 18 spread unifomly on the top half of circle of rad1us R meters. (1) Give an expression emagnitude of the electric ﬁeld at point P, the center of the circle. (ii) On the ﬁgure draw an arrow t. % dQ. ‘ 3' _
d: 1 ‘ mum V2 Y—axis at point P to show the direction of the electric ﬁeld at th
/)/)(U [Hints: Circle the correct symbol and ﬁll 1n the blank: Oset ds' be the tiny piece of arc that dQ sits on.) dQ = ' CPL gthe information above about (is, rewrite dQ.) dQ= “t (46 m.
A «2 Hats) , . A ; 4. L!
d5 2 R [0‘ 9) ’i' W ..............................
[ﬂ 375* ZWI 7L2 : {EfTLML'Y
................... 1T7 ‘ I
V0 qinao‘ Apply symmetry considerations now and circle the correct rthings 1n two sets of parentheses below: «112.... = Lisa—99: .................... O 059 ), 2117.09
® 2 JOE): jﬂ 6‘th sine rote _ dBp= Qjﬁ . (44' {,y _a7u$ oi , E ’ 91 \,’[9\L 6‘) U.) :> E. cv/Z/a? ‘IM
5‘ W ‘ 2'51“) ’ rim” P 17 60" ...
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