PHYSICS 208
EXAM B
October 12, 2010
NAME____________
PRiNT NAME
(10) 1. A 2 mm diameter wire of length 20 m has a resistance of 0.25
of the material?
Qm; C. 16x10
8
c2m; d.3.9x10
7
a.0.25; b.5x111
)m;
8
.
What is the resistivity
I
•2,
Y
3
ir(io’
20
(10) 2. If in the diagram I = 2 A, what is the potential difference between points a and b, and
which point is at higher potential?
a. 50 V, a higher; b. 50 V, b higher; c. 10 V, a higher; d. 10 V, b higher;
b
1O2
I
‘2
I
1V2
I
b
LO
44v
a-
(10) 3. A parallel plate capacitor is filled with a dielectric with K
the plate separation is 2 mm. The capacitance of the capacitor is
a.2lOnF; b53nF; c.l8nF; d.l3nF;
C
=
4. The plate area is 3 m
2 and
‘A
:
34(4
C
It)
f3 X1&
%
F
I
(10) 4. A 1 mF, 2 mF, and a 3 mF capacitor are connected in parallel, the combination being
connected across a 9 volt battery. The capacitor with the greatest charge on it is
a. the 1 mF; b. the 2 mF; c. the 3 mF; d. they all have the same
I$bF
C-
V
LY
6?3
--—-‘
(20) 5. The figure shows a system of four capacitors, where the potential difference across ab is
50 volts.
a. Find the equivalent capacitance of this system between a and b.
b. How much charge is stored in the 10.0 tF capacitor?
c. How much charge is stored in the 9.0 tF capacitor?
5.0F
10.0 jiF
)
90F
aHHb
—‘1 Hh
8.0F
jF
_j— __J_—
+--
4-
9tF
c_v
A—
4.- o77 .l-9j(L
(3.q7x,f’)522V
—J.73X1(--
(20) 6. For the circuit shown both meters are idealized, the battery has no internal resistance, and
the ammeter reads 1.25 A.
a. What does the voltmeter read?
b. What is the emf (voltage) of the battery?
vt :ZI,ZcALs,t
4
25.0 11
.‘r
35.0.f
z4
ZE
t
rLSh
I
•
.•
6M: qL
‘1
: Z3V4ZtZ’
:E
4
‘-‘I
-F
..
V
3S
r
;:
!c?Y
(20) 7. The capacitors in the figure are initially uncharged and are connected as shown with the
switch open. The voltage between a and b is 210 V.
What is the potential difference between c and d?
3.00 pF
6.00F
6.00F
3.00F
C-
4
a
4
C!
7i.z Ki6
4
_L
‘,
z
(P,LAf
13
1+
tL47O.6
9
5
c
jqov
V.-.i71’
V) 0
qo.-7DV’
1
2;oV
qx’o.4-r
Q
z
4 I1Af
eAc
.Lf
J
kIAI,(