PHYS 102-4M
Exam 2, Chapters 19 & 20
8 March 2007
Name______________________
Constants
mp= 1.673×10-27 kg
me= 9.109×10-31 kg
e = 1.6×10-19 C
µ○=4π×10-7 T·m/A
_____1.
What is the equivalent resistance of this circuit?
(A)
a) 69 Ω
b) 33.02 Ω
c) 72 Ω
d) 176 Ω
_____2.
Which of these equations is appropriate for this circuit?
a)
b)
c)
d)
a)
b)
c)
d)
(B)
-45-1I3-40I2-80-1I3=0
45-1I3-40I3-30I1=0
30I1+45-1I3-40I3=0
80-1I2-20I2-45-1I3-40I3=0
_____3.
a)
b)
c)
d)
What purpose does the third prong on a three-prong outlet serve? (D)
No purpose
Allow for more stability in the outlet
An alternative to the European system of electrical outlets
Act as a ground thus providing a safety feature
_____4.
What is the equivalent capacitance of this circuit if C1=1.0 µF, C2=2.0 µF,
and C3=3.0 µF? (B)
a)
b)
c)
d)
_____5.
0.8 µF
2.2 µF
6.0 µF
8.0 µF
What is the terminal voltage of a battery with an internal resistance of 1 Ω
and an emf of 10 V when the battery is connected in series with a 100 Ω
resistor? (C)
a)
b)
c)
d)
e)
_____6.
a)
b)
c)
d)
9V
8.2 V
9.9 V
7.3 V
-4 V
A 700 Ω and a 300 Ω resistor are connected in series with a 10 V battery.
What is the voltage across the 300 Ω resistor? (A)
3V
7V
10 V
-2 V
_____7.
a)
b)
c)
d)
What is the voltage across the 820 Ω resistor in this circuit? (D)
1.4 V
6.7 V
2.3 V
5.3 V
_____8.
In an RC circuit, the resistance is 2 Ω, and the capacitance is 6 µF. What is
the time constant for this circuit? (B)
a) 12 s
b) 1.2×10-5 s
c) 3 s
d) Need the voltage of the battery to calculate the time constant
_____9.
When 2 or more resistors are connected in parallel to a battery, (D)
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
c) the equivalent resistance of the combination is less than the resistance of
any one of the resistors
d) all of the above
_____10. Three identical resistors are connected in series to an ideal battery with V=12
V. What is the potential across each resistor? (C)
a) 2 V
b) 3 V
c) 4 V
d) 6 V
_____11. In which of these circuits will the light bulbs give more light, assuming the
batteries are identical? (B)
a) 1 (series)
b) 2 (parallel)
_____12. In this RC circuit, the time constant is 1 µs and the resistance is 10 Ω. What is
the capacitance, C? (C)
a)
b)
c)
d)
e)
1 µF
10 µF
0.1 µF
0.1 µC
2F
_____13. Two 5 Ω resistors are in series with a 10 V battery. What is the current
through the first of these resistors? (B)
a) 5 A
b) 1 A
c) 0.5 A
d) 2 A
_____14. If you increase the number of resistors in parallel, the equivalent resistance
(B)
a) increases
b) decreases
c) stays the same
_____15. The emf of this battery is E=2 V, the internal resistance is r=0.1 Ω, and the
terminal voltage is Vab=1.8 V. What is the current through the battery? (B)
a)
b)
c)
d)
1A
2A
4A
6A
_____16. A proton has a velocity of 10 m/s and is traveling perpendicular to a magnetic
field with B=1 T. What is the magnitude of the force on the proton? (A)
a)
b)
c)
d)
1.6×10-18 N
3.2×10-19 N
4N
-1.6×10-19 N
_____17. What is the magnitude of the magnetic field at point P if the current is 10 A?
(B)
a)
b)
c)
d)
1T
2×10-5 T
3×10-6 T
2×10-4 T
_____18. In the figure for question # 17, what is the direction of the magnetic field at
point P? (C)
a) to the left
b) to the right
c) into the page
d) out of the page
_____19. In this figure, an electron (q) has a velocity pointed upwards (represented by
the arrow). The direction of the magnetic field is given by the X’s. What is
the direction of the force due to the magnetic field on this electron? (B)
a)
b)
c)
d)
to the left
to the right
into the page
out of the page
_____20. How much current is flowing in a wire 10 meters long if the force on it is 1 N
when placed perpendicular to a 0.1 T magnetic field? (A)
a) 1 A
b) 2 A
c) 5 A
d) 0.1 A
_____21. If you cut a magnet into two pieces, one piece will be the north pole and the
other will be the south pole. That is, you will get isolated north and south
poles.(B)
a) True
b) False
_____22. Opposite poles of a magnet (A)
a) experience an attractive force
b) experience a repulsive force
c) neither attract nor repel
_____23. A proton has a velocity of 3×105 m/s that is at an angle of 45○ to the magnetic
field of 1 T. What is the magnitude of the force that it experiences? (B)
a)
b)
c)
d)
2×10-14 N
3×10-14 N
4×10-14 N
5×10-14 N
_____24. A proton beam enters into a magnetic field region as shown in this figure.
What is the direction of the magnetic field B?
(D)
a)
b)
c)
d)
e)
up
left
right
into the page
out of the page
_____25. An electron has a velocity of 5.0×106 m/s that is perpendicular to a magnetic
field of 2.0 T. What is the radius of the path that the electron follows? (B)
a)
b)
c)
d)
2.8×10-5 m
1.4×10-5 m
4.2×10-5 m
3.2×10-5 m
_____26. GFCI outlets have a device that measures: (B)
a) the voltage
b) the incoming and outgoing currents
c) the temperature
d) the humidity
_____27.
The Earth’s magnetic north pole is closest to the Earth’s geographic (B)
a) North pole
b) South pole
_____28.
The force on a charge whose velocity is parallel to the magnetic field is
always (A)
a) zero
b) positive
c) negative
_____29.
Two particles with equal charges but different masses enter the same
magnetic field. Which has the path with the largest radius? (A)
a) the more massive particle
b) the less massive particle
_____30.
The magnetic force on a charged particle is always (A)
a) perpendicular to the particle’s velocity
b) parallel to the particle’s velocity
_____31.
Kirchoff’s loop rule states: (A)
a) The sum of the voltages in a closed loop is zero
b) Kirchoff was loopy
_____32.
a)
b)
c)
d)
into the page
out of the page
left
right
_____33.
a)
b)
c)
d)
e)
What is the direction of the magnetic field at point P? (B)
2A
3A
5A
6A
10 A
What is the current in branch P? (D)