This preview shows pages 1–5. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Q.1. A cylindrical wire of radius a and length L is lying 7
along the x—axis as shown in the ﬁgure. The resistivity of the wire varies as p(x) = p0 (1+ x2/2L2) where pc is a
constant. A potential difference of V is applied between the ends of the wire. a) What is the resistance dR of the wire segment of very short
length dx, at the position x, in terms of po, x, a, L and dx? chat '2 SCY)‘PQX/A
(lRL'gJa ((4 )%§—L b) Calculate the resistance of the whole wire in terms of pm a and L. L
Rzgofﬂ.
6 L ‘5 .35.
29 5 .1: QB ‘  Z _
T4136“ £519?“
:_E_ EL
5 "Trqq % 0) Calculate thecurrent passing through the wire in terms of V, pa, a, and L. :1; = a... a V
R 3: t, L.
6 tr at
1 6 \I we“ .
‘1? ‘g 9 L '
3 d) Calculate the current density in the wire in terms of V, p0, and L.
)5 :.. E.
A
a; it);
7t L51 L‘ e) Calculate the electric ﬁeld in the wire at the point where x = LB, in terms of V and L. Eb!” : (W
E u_ : Aggy“.
(3‘ go<4+ L1: qL’YU
2 l‘ Q_\ _ 1 t,
6.?Wm.
J V817“
‘1— L ex
< 'iLS’o A E.a\8V B £._u2u0\{
C
.115 '
Q.2. Directions of the‘cu'n‘ents and the numerical values ‘i‘n‘i‘J 3' ~ 5 5' VF? 5‘: w "5* ‘ " r"
u 5 ' u a , ;. 7  _ . 1 =_ . of emfs and resmtances of the mulltlloop curcmt are n sit1:9 ‘   ~ ' , u ..  » I ,v ,1
given on the ﬁgure. fezss‘mamrm ew ajgglusga cs: x 1.5.: 7: .;;.,,3;,,;r;.«,
‘J ‘ A: :21: £3121.qu . ' ' " l ‘ ' an
a) Write down the Ioop equatmn for the loop ‘1: 5m m, .e . . = , , _ “f:
ABEFA (Use the numerical values ofemf’s and _ '45? MM.“ .! _,_ “Angle; 3.1% {5 W ﬂ. W. b resistances). .l . .3 i Us: 7:. V . _ _, , .1 :ij. Us???” I“ _; ﬁg. 1, ‘ 4: +4.11 ‘+"«:,“I, =0 ' ' ' ~ '   ‘ I b) write down the 100? equation for the loop BCDBB. (Usetthelnhmerical values and i resistances). Jz~§44_r323_1;ez=o Z—ZIJH‘IZEO z—zr3_61;=o c) Write down thejunction equation for the junction E. (In terms of currents I;,I;,i3).
2; ""‘ r3 " r2.
I; 4 2:, 2 I;
d) Calculate the currents 11, [2, and i3.
_¢e+aILeézrifsl=° get—“l ::E£=.—‘LA
z 1? +102“ ~41" =o
z .5 I‘fz—fan‘fa(HZIESA *4I4I‘3jllfzro I I;ng
_______‘_____________._.__.—.
1',1A 12. +u1‘z D I;rA II 2‘.._.2A q
.al‘ e) Calculate the potential difference VA — VD, between the points A and D. VA_V0 ___. g’r’_[_3r3 ._._ 4‘3 {x{..2.}=l 4212 e/4v wig—v0 arr—1+529—r3—1rl—1JH = “V “V
1) Calculate the total power dissipated as heat in the resistors of the circuit.
A: .3sz, w 3‘” ﬂufa‘ﬁréw
[92:17:21, 1W P4213224=4w F550“?
#7. : 5‘0 W g) Calculate the total power delivered by the batteries. Is the energy conservation satisﬁed? 3} a £5, ,3“: a H w rrvrﬂw'ns) 2;; : uffal EL 5: ~4W («braybang) _
i F few (2.3. A wire of mass m = 10 g, length L = 20 cm and resistance  0 ~ .0 R x 0.10 9 is connected to two identical springs each of spring .
constant k : 4.0 me. Other ends of the springs are connected to a switch S and a battery of emf 8 = 10 V as shown in the k k
ﬁgure. The system is in the horizontal plane, points C and D are ' ﬁxed and the wire is on a frictionless, horizontal table. 0 o E
The wire is in a uniform magnetic ﬁeld of B = 2.0mT, which is in vertically upward direction. When the springs have their natural 9 0
lengths, switch S is ciosed.(Assnme that the springs and ' connection cables have no resistance). a 0 a a D @
0 L’ a) Will the springs compress or extend? Explain brieﬂy how you determined your answEi‘B;
.Tlne Spring/s an“ axiemdia bacaaet
l‘ “T: i a I
ilk dives/from 6:] i]; 15 awn! from #18 Eating. 0U!“ extend
q . 0 S) b) How much is the ﬁnal compression or extension when the equilibrium is reached? ‘0 __ i __ l0 .. i a a.
ﬁerLBsme—UHOJHZMO :)3m90=]+,‘(m N In €?uihbﬁ tum. scale.) {23} (force (M the wire ,‘3 mam. Hence, lit)“: F3
2 _3
=5 7%: F“ = “to N ==5Xl0m
EL: 2K4N/m Xa=5xI03m 0 it c) What is the total stored energy in the springs when the equilibrium is reached? .?2 ii =Z/3<(%)<x’”)w= tN/Mxﬁm m)
a: [011 éouiex ll II ‘4 I 2
l0 you. as
0 if d) Now the switch 3 is opened suddenly. What is the initial acceleration of the wire? when Hie 5W\L+Ci/k is crested) F3 30% 4:: zero. Mai orce examine wire. is ,zkxo. Home.
3 _ _ 231; SM)"
ztxaqizao =3 aojﬁ—wrmal scam/Sal G) e 6 I 3’ Q.4. proton enters into a uniform magnetic feild of B a: 1.0 k T I i I I e 9 ° _ . f
with a velocity ofv =1.9 x :07; m/s as shown in the ﬁgure. I .6 I IEII I I I II
a) Find the magnetic force acting on the proton at the moment it ‘ _I I II
enters into the magnetic field. Give it in unit vector notation. (a 9 e I
A ,I ‘7 I A  I . l .
F a C1 v x 13 II . III a a e a
A? m I x
@ 4mm cﬂI‘Mo /5)(10T) if
I If a o o
.— {L A . N» a ,m ' b) Draw the orbit of the proton in the magnetic ﬁeld on the above ﬁgure. Calculate the radius of its
orbit. : a *1? 1. I?
F m 4. WW Unix“? x10 “/.) I r ‘15 (tamo'mc) (4.0T)
@ “i N lxlo'lm 90‘2M = . x10 m ’”
H:
c) Calculate the angular frequency of the proton.
q
I. . O “1/5 3’
a): 5L: Ml" : 93w) ract/s r 0.1m @ d) Find the period of the proton. , .l“ 7~5x lo"f fora/S _ "l
ﬂew" 6; 066% l0 s CUT; ’ '
_.— @ i w (“1‘31 [0} 6" "T 8
6 6x10 3 e) What is the work dOne by the magnetic ﬁeld on the proton during the four complete turns? * 1"" “" » “were: (damJam
[Fiatt: hﬁgtt ., {2ch MCIIIIIIIE «at for’1"?  ﬂhb 5
Power: Fa V=O because Fix: Q.5. The3 current in a cylindrical wire of radius R : is not .1 :u. 325 an: utter 3:4: w
uniformly distributed, but the current density varies pi . :3 ‘ ,:E W 2:12. .m m ‘
linearly from the center as j = A (r/R), where A is a
.3."constant and r is the distance from the axis of the wire. 2e : ® a) Determine the magnetic ﬁeld ( in terms of ye, A, R and r) 3
inside the wire, where r < R. . 2 ~ ': Em”: .I r v
3m? .=> glean v.1 r=53ts=get~map
§BAQ=B§AQ=ZWVE 1:2!!5. Efﬂzém
‘8‘ O
A WA
wwg=ﬂ°fec V3 :1“; Y:
A 1..
B=ﬂ03R r
B:ﬁ.\r" ® 1)) Determine the magnetic ﬁeld ( in terms of no, A, R and r) outside the wire, where r > R. at: . g " “I mﬁ°£
3%.
L I: g—gv zwwév
B =. VLL‘R “L— °
3 r x_ 2.813: F;—
:i“ g ‘3
AR“
Bg/N 35“ G) Show that the equations of part a and b yieId the same result for the points on the surface of the
wire, where r = R. FH'OVVK M'k 7 = “L 1' ‘w. = = ch:
3' a) B y 3K'r 5. ? st=~> e ju 3
A FMM b) _¢£‘3—R; §nV‘ Y‘='P\‘ B: 0T3 ...
View Full
Document
 Spring '11
 NoProfessor
 Physics

Click to edit the document details