Phys222 W16 Quiz 3_2: Chapters 28, 29 Key
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Please mark your answer clearly here and in the scantron!
1.
What is the potential difference VB – VA when the I= 1.5 A in the circuit segment
below?
20 Ω
I
A
20 V
2.
–
12 V
+22 V
–22 V
–38 V
+38 V
+2.0 V
a.
b.
c.
d.
e.
B
+
+
–
<=
Determine the resistance R when I = 1.5 A.
+
50 V
+
–
30 V
R
I
–
20 Ω
10 Ω
a.
b.
c.
d.
e.
3.
40 Ω
8.0 Ω
85 Ω
28 Ω
32 Ω
<=
If R = 2.0 kΩ, C = 4.0 mF, Ε = 8.0 V, Q = 20 mC, and I = 3.0 mA, what is the
potential difference Vb – Va?
R
a
a.
b.
c.
d.
e.
+7.0 V
+19 V
+9.0 V
–3.0 V
–14 V
+
+
Q
C
–
–
I
+
–
b
E
<=
1
Phys222 W16 Quiz 3_2: Chapters 28, 29 Key
4.
At what rate is thermal energy generated in the 20-Ω resistor when ε = 20 V?
40 Ω
+
30 Ω
E
30 Ω
30 Ω
–
20 Ω
a.
b.
c.
d.
e.
5.
<=
In an RC circuit, how many time constants must elapse if an initially uncharged
capacitor is to reach 80% of its final potential difference?
a.
b.
c.
d.
e.
6.
6.5 W
1.6 W
15 W
26 W
5.7 W
2.2
1.9
1.6
3.0
5.0
<=
At t = 0 the switch S is closed with the capacitor uncharged. If C = 50 µF, ε = 20
V, and R = 4.0 kΩ, what is the charge on the capacitor when I = 2.0 mA?
S
I
+
+ +Q
E
– –C
–
R
a.
b.
c.
d.
e.
7.
360 µC
480 µC
240 µC
600 µC
400 µC
<=
A 2.0-C charge moves with a velocity of (2.0i + 4.0j + 6.0k) m/s and experiences
a magnetic force of (4.0i – 20j + 12k) N. The x component of the magnetic field is
equal to zero. Determine the y component of the magnetic field.
a.
b.
c.
d.
e.
–3.0 T
+3.0 T
+5.0 T
–5.0 T
+6.0 T
<=
2