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Unformatted text preview: Name: Class: Date: ID: A Physics 196 Fall 2010 Practice Test for Midterm III Multiple Choice
Identify the choice that best completes the statement or answers the question. 1. What is the magnitude of the magnetic ﬁeld at point P if a = R and b = 2R? e. —_ 2. A long straight wire (diameter = 2.0 mm) carries a current of 40 A. What is the magnitude of the magnetic
ﬁeld 1.5 mm from the axis ofthe wire? a. 3.0 mT
b. 12 mT
c. 5.3 mT
d. 7.4 1111"
e. 8.0 mT 3. Three coplanar parallel straight wires carry equal currents I as shown below. The current in the outer wires is
directed to the right, and that in the middle wire is directed to the left. Each pair of wires is a distance a apart.
The direction ofthe magnetic force on the middle wire w
w I
——————mg._________ is up out ofthe plane ofthe wires. is dowu into the plane of the wires. is in the plane of the wires, directed upwards. is in the plane of the wires, directed downwards cannot be deﬁned, because there is no magnetic force on the middle wire. rue.0279: Name: ID:A . A 40turn circular coil (radius = 4.0 cm, total resistance = 0.20 Q) is placed in a uniform magnetic ﬁeld directed perpendicular to the plane of the coil. The magnitude of the magnetic ﬁeld varies with time as given
by B = 50 sin(10 :11) mT where t is measured in s. What is the magnitude of the induced current in the coil at 0.10 s? a. 50 mA
b. 1.6 A
c. 0.32 A
d. zero e. 0.80 A . A long solenoid has a radius of 2.0 cm and has 700 turnsfm. If the current in the solenoid is decreasing at the rate of 8.0 AIS, what is the magnitude of the induced electric field at a point 2.5 cm from the axis of the
solenoid? a. 56 ,qu
b. 8.8 prm
c 88 ,uVlm
d. 69 ,qum
e. 44 ,uVI'm . A series LC circuit contains a 100 mH inductor, a 36.0 mF capacitor and a 12 V battery. The frequency of the electromagnetic oscillations in the circuit is
a. 5.?3 x 10—4 Hz. b. 9.55 X 10‘3 Hz. c. 0.442 H2. d. 2.66 Hz. c. 44.0 Hz. When a switch is closed, completing an LR series circuit, the time needed for the current to reach
three—quarters its maximum value is __ time constants.
a. 0.500 b. 0.693 c. 0.725 d. 1.33 e. 1.38 . The power output, PM, of an ideal stepup transformer that receives power input, Pin, and which has N1 turns in the primary and N2 turns in the secondary coil is given by a. Pmlt=Piﬂ'
N2
b Pout—‘N—lpm
NI
C pout—N—2Pl1'l
N, 2
d Pout: N— Pi
l
e P0111 F Pin
2 Name: ID: A 9. The graphs below represent current and voltage phasors at one instant of time. The solid arrows represent the
voltage phasors, 13me, and the dashed arrows represent the current phasors, 1m“. The graph which shows the
correct relationship between current and voltage phasors for a capacitor in an RC circuit is e.
10. Determine the rms current for the circuit. 1m 12!
$=1E§né§ﬁ§ﬂ> 1111‘ 55 mA
T? mA
99 mA
0.190 A
61 mA 99.057!» Physics 196 Fall 2010 Practice Test for Midterm III
Answer Section MULTIPLE CHOICE
I. ANS: D PTS: 1
2. ANS: C PTS: 1
3. ANS: E PTS: 1
4. ANS: B PTS: 1
5. ANS: A PTS: 1
6. ANS: D PTS: 1
7. ANS: E PTS: 1
8. ANS: A PTS: 1
9. ANS: C PTS: 1
IO ANS: A PTS: 1 1]): ...
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 Fall '08
 Bocker
 Physics

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