J:.xam,<Ul.l..
/l'nl~I\"'~L.D
;:)l'I'-U'IIuLU!U
Name_Professor S. K. Sinha _ _ _ _ _ _ _ _ _ _ _ _ _ __
f.l = 4.
'it .
10"-7 = 1.26 . 101\-6 N/A2 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Figure 30.1
+-20cm-+
a
X
X
X
X
X
X
X
X
X
f
20cm
b
100
!
1) In Figure 30.1, a wire and a 10 ohm resistor are llsed to form a circuit in the shape of a square, 20 ern by 20 em.
A uniform but non-steady magnetic field is directed into the plane of the circuit. The magnitude of the
magnetic field is decreased from 0.90 T to 0.30 T in a time interval of 60 ms. The averapduced current and
its direction through the resistor, in this time interval, are dosest to:
A) 40 rnA, from a to b
lW \ <D=('#l)=~~!
B) 40 rnA, from b to a
C) 60 rnA from a to b
D) 24 rnA. from b to a
E) 24 rnA, from a to b
.kr6T , ~fJj vn
"L
Figure 30.4
~
Q4
--10
-- • 0'1
Vt1
-- .4
It ~ b~
a..
~
b~ R~R
Wire is wound on a square frame, 30 cm by 30 em, to form a coil of 4 turns. The frame is mounted on a horizontal shaft
through its center (perpendJcular to the plane of the diagram). The coil is in clockwise rotation, with a period of 0.01 s: A
uniform, horizontal, magnetic field of 0.80 T is present. At a given instant, the plane of the coil forms a 60" angle wi,th the
horizontal, as shown.
2) In Figure 30.4, at that instant, the emf induced in the coil is closest to:
A) 11 V
B) 18 V
~ ,,~(" ~~
-~ -=. \ =)
C) 16 V
D) 9 V
.been • I Se
E) 13 V
r
.... f::; 10 .:::.) W == 2-0 71 I =(.0 ~)(I~) S~()(t.J+)~ ~ E=(.O!{J~ 'lOll: CO$(W1
;.
c- . 72· lfx
n blA-,,"~he
B
~ Cfv
f'\1
LV+=60'~c.csCLV~)'
r .
A-I
J'Y
E:= •07~ •J-O-71 o
,----,--­
~
,.,..~
~
d tit '5
~(,~"V'
~ Iu. J.
3) In Figure 30.5, a coil of wire is placed on the axis of a solenoid carrying a DC current. Which of the following.
will NOT result in an EMF being induced in the coil?
~MOVetheCoiltowardPOintP. ~ S:r,.c...e Q ~~ ) ~
) otate the coil about the z-axis.
+h.( e 10 il ,. ~ 0
Rotate the coil about the y-aXis:>D) Rotate the coil about the x-axis
E) Change the current in the solenoid.
reo
\A
~r w. n e
;11( C
~:.s
h
.,/ c. 4*'5 <.s
......."
.
"e.+
ttl,,~ +1c.a.)(
.(:' (
ctx
1"'\
J'::)'
u
0&.4
~ &.( oS ....(~X' 41\0"
Situation 31.1
An 18 mH solenoid inductor is ''''ound on a form 0.80 m in length and 0.10 m in diameter. A coil is tightly wound around the
solenoid at its center. The coil resistance is 5.0 ohms. The mutual inductance of the coil and solenoid is 60 !-lB. At a given
instant, the current in the solenoid is 300 rnA, and is decreasing at the rate of 2.5 A/s.
4) In Situation 31.1, at the given instant, the induced emf in the solenoid is dosest to:
A)4SmV
L
B)3OmV
m,
C)3SmV
E -- L~
I.
D)40~V
...
E) 50mV
o
M
J.I
r-.:....J-z.
p.. "",$ '" ASl&4,.,e.
~t.rn~
,s conS~.
Jf - \" Ats <0:1
'I1. :. .c.0(l.r~;
A." tJ. JI1 wJ .~ J. et'..s
~
}1~JO-3. ~S
--
45mV
nnJ.
I
, -:L.
-=
C()'Jfn'b.t I.e
C1-~ -r:r:­
cAT,
-
R
~
«T
so,.~~±~
A-2
d