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 DocumentThis 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: OLD EXAM II 1. When two or more resistors are connected in parallel to a battery, a. The voltage across each resistor is the same.
b. The total current ﬂowing from the battery equals the sum of the currents ﬂowing through each resistor.
The equivalent resistance of the combination is less than the resistance of any one of the resistors. c.
~—~> All of the above. 2. A 6.0 Q and a 12 Q resistor are connected in series to a 36 V battery. What
power is dissipated by the 6.0 Q resistor? ~—>’ 24w . 48 W
o. 12 W
d. 6.0 W 3. Determine the current in the 7 Q resistor. a. 1.1 A
b. 0.75 A . 1.8A
‘—> 2.1 A 4. Kirchhoff’s voltage rule for a closed loop is an example of “9 Conservation of energy.
b. Conservation of charge.
0. Conservation of momentum.
d. None of the above. 5. What is the total circuit resistance? R1 = 10 Q a.
b. 800 550 R2: _
500 E 209 “3‘20“
350 R4=300 6. A 14 A current ﬂows into a parallel combination of a 3.0 Q and a 4.0 Q resistor.
What current ﬂows through the 3.0 Q resistor? é__,
b cf
d. 8.0 A
7.0 A
6.0 A
5.0 A 7. As more and more capacitors are connected in series, the equivalent capacitance
of the combination increases. a.
b.
c. “>0 Always true. Sometimes true. It depends on the voltage of the battery to which the
combination is connected. Sometimes true. it goes up only if the next capacitor is larger than the
average of the existing combination. Never true. 8. 5.00 “F, 10.0 JF, and 50.0 uF capacitors are connected in series across a 12.0 V
battery. What is the potential difference across the 10.0 uF capacitor? a. 1.25 v b. 2.50 v —~> 3.75 v
5.00 v 9. A vertical wire carries a current straight up in a region where the magnetic ﬁeld
vector points due north. What is the direction of the resulting force on this current? a. Down
Nonh b.
. East
_._.. w... 10. What is the force per meter on a straight wire carrying 5.0 A when it is placed in
a magnetic ﬁeld of 0.020 T? The wire makes an angle of 27° with respect to the magnetic ﬁeld lines. a. 0.022 N
———~> 0.045 N c. 0.17 N d. 0.26 N 11. A proton moving at 5.0 x 104 m/s horizontally enters a region where a magnetic
ﬁeld of 0.12 T is present, directed vertically downward. What force acts on the proton? l
0.0.0.0) Zero 3.2 x 10'16 N
6.4 x 10'16 N
9.6 x 10'16 N 12. Which of the following is correct? a. b.
6‘, Q)
d. When a current carrying wire is in your right hand, thumb in the direction
of the magnetic ﬁeld lines, your ﬁngers point in the direction of the current.
When a current carrying wire is in your left hand, thumb in the direction of
the magnetic ﬁeld lines, your ﬁngers point in the direction of the current.
When a current carrying wire is in your right hand, thumb in direction of
the current, your ﬁngers point in the direction of the magnetic ﬁeld lines.
When a current carrying wire is in your left hand, thumb pointing in the
direction of the current, your ﬁngers point in the direction of the magnetic
ﬁeld lines.  13. Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions.
The wires are separated by 0.20 m. What is the magnetic ﬁeld midway between the two wires? a. 1.0X10'5T
3.0 x10'5T b.
. 4.0 x10'5T
3......) 5.0 X10'5T 14. Two long parallel wires carry currents of 5.0 A and 8.0 A in the opposite
directions. The wires are separated by 0.30 m. Find the magnetic force per unit
length between the two wires. a. 2.7 x 10'5 N attractive b. 7.2 x 10'5 N attractive ~——> 2.7 x 10'5 N repulsive
7.2 x 10'5 N repulsive 15. How much current must pass through a 400 turn coil 4.0 cm long to generate a
1.0 T magnetic ﬁeld at the center? a. 0.013 A
b. 13 A
c. 40 A M. 80A 16. A circular wire loop of area 0.25 m2 carries a current of 5.0 A. The coil lies in a
horizontal plane with the current ﬂowing in the counterclockwise direction when
viewed from above. At this point, the earth’s magnetic ﬁeld is 1.2 x 10“ T
directed 60° below the horizontal. What is the magnitude of the torque which
acts on the loop? a. 2.5 x 105 mN
b. 5.0 x 105 mN
2“). Q9 7.5 x 10'5 mN
d. 1.0 x 104 mN 17. A circular loop of radius 0.10 m is rotating in a uniform magnetic ﬁeld of 0.20 T. Find the magnetic ﬂux through the loop when the plane of the loop and the
magnetic ﬁeld vector are perpendicular. a. zero
b. 3.1 x 10'3 T°m2
c 5.5 x 10'3 Tom2 ~—~—> 6.3 x 103Tm2 18. Faraday’s law of induction states that the emf induced in a loop of wire is
proportional to a. The magnetic ﬂux.
b. The magnetic ﬂux density times the loop's area
“—9 The time variation of the magnetic ﬂux current divided by time. 19. A circular coil lies ﬂat on a horizontal table. A bar magnet is held above its center
with its north pole pointing down, and released. As it approaches the coil, the
falling magnet induces (when viewed from above) a. No current in the coil.
b. A clockwise current in the coil.
~> @ A counterclockwise current in the coil.
. A current whose direction cannot be determined from the information provided. 20. Suppose that you wish to construct a simple AC generator with an output of 12 V
maximum when rotated at 60 Hz. A magnetic field of 0.050 T is available. If the
area of the rotating coil is 100 cm2, how many turns are needed? a. 16 b. 32
———9 © 64 d. 128 21. A pure capacitor is connected to an AC power supply. In this circuit, the current A...) Leads the voltage by 90°
. Lags the voltage by 90° c d Is in phase with the voltage
None of the above 22. What is the current through a 2.50 mH coil due to a 110 V, 60.0 Hz source? a. 0.94 A
2.5 A b.
. 104A
Mb 117A 23. What capacitance is needed in series with a 100 Q resistor and 15 mH coil to get
a total impedance of 110 Q at 2000 Hz? A. 0.14 mF
46 pF B.
. 10 [JP
9...» Q) 0.56 JF 24. What is the resonant frequency of a 1.0 JF capacitor and 15 mH coil in series? a. 15 kHz ———————> . 1.3 kHz
0. 0.77 kHz
d. 67 Hz ...
View
Full Document
 Spring '08
 Coleman

Click to edit the document details