Download Test- FaF97

PHYSICS 202
Final Exam
NAME____________________________________________________
1. A 400 nm thick film of kerosene (n=1.20) is floating on water. White light is normally incident on
the film. Which one of the following visible wavelengths (in air) has a maximum intensity in the
reflected light?
A.
B.
C.
D.
E.
F.
400 nm
420 nm
480 nm
540 nm
600 nm
720 nm
2. A long, straight wire carries a current I. If the magnetic field at a distance d from the wire has
magnitude B, what is the magnitude of the magnetic field at a distance 2d from the wire?
A.
B.
C.
D.
E.
F.
0.0625 B
0.25 B
0.5 B
2.0 B
4.0 B
16.0 B
3. When an object is placed at the proper distance to the left of a converging lens, the image is focused
on a screen 25.0 cm to the right of the lens. A diverging lens is now placed 15.0 cm to the right of
the converging lens, and it is found that the screen must be moved 50.0 cm further to the right to
obtain a sharp image. What is the focal length of the diverging lens?
A.
B.
C.
D.
E.
F.
-8.0 cm
-10.0 cm
-12.0 cm
-15.0 cm
-20.0 cm
-24.0 cm
FaF97
4. A rectangular wire loop is pulled with a force F
to the right. At the instant shown in the figure,
the loop is partially in and partially out of a
uniform magnetic field that is directed into the
paper. As a result of the force F, the loop
moves to the right at a constant speed of 8.0 m/
s. The magnitude of the field is 1.2 T. The
loop has a length of 0.12 m, a width w=0.08 m,
and a resistamce of 200 Ω. Determine the
magnitude of the force F required to keep the
loop moving at the constant speed, 8.0 m/s.
A.
B.
C.
D.
E.
F.
×
×
×
×
×
×
×
×
× w×
×
×
×
×
×
×
×
×
×
×
R
v
0.00923 N
0.00369 N
0.00185 N
0.00147 N
0.00074 N
0.00037 N
5. The figure shows four parallel plate capacitors: A, B, C, and D. Each capacitor carries the same
charge Q and has the same plate area A. As shown in the figure, the plates of capacitors A and C
are separated by a distance d while those of B and D are separated by a distance 2d. There is a
vacuum (K=1) between the plates of capacitors A and B; and there is a dielectric (K=5) between
the plates of capacitors C and D. Which capacitor(s) has the largest potential difference between its
plates?
A.
B.
C.
D.
E.
F.
A
B
C
D
K=1
K=1
K=5
K=5
d
2d
d
2d
A
B
C
D
A and B are the same and smaller than C or D.
A and B are the same and larger than C or D.
FaF97
A.
B.
C.
D.
E.
F.
×
×
×
B into page
×
×
×
×
×
×
×
×
×
×
×
× R` ×
×
×
× R“×
×
×
×
V
+
6. A mass spectrometer is used to
separate two of the isotopes of
mercury(Hg) whose masses are
m1, m2 where m2>m1. Atoms of
the two isotopes are ionized and
exit a source with the same charge
+e. The charged atoms are first
accelerated through a potential
difference V; they then enter a
constant, uniform magnetic field
B as shown. If R1=0.6075 m and
R2=0.6135 m, what is the value of
the ratio m1/m2?
source of
ionized atoms
of the isotopes
collecting plate
×
0.9751
0.9805
0.9848
0.9901
0.9952
0.9998
7. Consider three identical metal spheres, A, B, and C. Sphere A carries a charge of -2.0 µC; sphere B
carries a charge of -6.0 µC; and sphere C carries a charge of +5.0 µC. First, spheres A and B are
touched together and then separated. Spheres B and C are then touched and separated. Does
sphere C end up with an excess or a deficiency of electrons, and how many electrons is it?
A. deficiency, 8.35×1011
B. deficiency, 3.12×1012
C. excess, 7.80×1012
D. deficiency, 9.36×1012
E. excess, 1.15×1013
F. excess, 1.40×1013
8. In a nuclear reactor, mass is annihilated at the rate of 1.0 microgram/sec. If 70% of the energy
produced is converted to electrical power, what is the electrical power output?
A.
B.
C.
D.
E.
F.
63 megawatts
30 kilowatts
45 megawatts
60 kilowatts
300 watts
300 kilowatts
FaF97
9. An FM radio station broadcasts radio waves whose frequency is 102.4 MHz. What is the
wavelength of these radio waves?
A.
B.
C.
D.
E.
F.
2.82 m
2.93 m
3.04 m
3.13 m
3.22 m
3.31 m
10. Three point charges - Q, +3 Q, and - Q
are arranged along a line as shown in
the sketch. The electric potential at
point P is
VP = c
P
kQ
R
where c is a constant. The value of c is
R
-Q
+3 Q
R
A.
B.
C.
D.
E.
F.
-Q
R
+1.00
+0.879
+1.59
-1.00
-0.879
-1.59
11. When a 1500 W hair dryer is in use, the voltage applied across the dryer may be represented as V=
155.6 sin(120πt) volts. What is the rms current in the dryer? (Note, you are asked for the rms
current, not the peak current.)
A.
B.
C.
D.
E.
F.
19.28 A
13.63 A
9.64 A
6.82 A
4.82 A
3.41 A
FaF97
A.
B.
C.
D.
E.
F.
1Ω
3Ω
+
E`
+
12. Three resistors and two
batteries are arranged as
shown in the circuit
diagram. If E1=1 V and
E2=6 V, the magnitude of
the currents in E1 and E2
are, respectively,
E“
3Ω
0.8 A and 1.4 A
0.4 A and 1.2 A
0.8 A and 1.2 A
0.8 A and 0.6 A
0.4 A and 0.8 A
0.4 A and 1.4 A
13. Two particles of the same mass carry charges Q1=+3.0 C and Q2=-2.0 C, respectively. They are
shot into a region that contains a uniform electric field as shown. the particles have the same initial
velocities in the positive x direction. The lines labeled a through e, indicate five possible paths for
the particles. If the electric field points in the negative y direction, which paths could correspond to
a path taken by each of these particles?
a
y
b
x
c
E
d
point of entry
e
A.
B.
C.
D.
E.
F.
path a for Q1 and path d for Q2
path c for Q1 and path b for Q2
path d for Q1 and path e for Q2
path b for Q1 and path a for Q2
path b for Q1 and path e for Q2
path e for Q1 and path b for Q2
FaF97
×
A.
B.
C.
D.
E.
F.
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
×
Magnetic Field (T)
14. A circular loop of copper wire with an area of 2.0 m2 lies in a plane perpendicular to a timedependent magnetic field pointing into the page as shown. The time dependence of the magnitude
of the magnetic field is shown in the graph. Which statement is correct?
10
5
0
2
4
6
Time (s)
8
10
At t=1 s the induced emf is 2.5 V; the induced current is clockwise.
At t=4 s the induced emf=2.5 V; the induced current is clockwise.
At t=4 s the induced emf=5 V; the induced current is counter-clockwise.
At t=7 s the induced emf=20 V; the induced current is clockwise.
At t=7 s the induced emf=10 V; the induced current is clockwise
At t=9 s the induced emf=1 V; the induced current is counter-clockwise.
15. Determine the length of a copper bar that has a resistance of 0.172 Ω and a cross-sectional area of
1.0 cm2. The resistivity of copper is 1.72×10-8 Ω•m.
A.
B.
C.
D.
E.
F.
0.1 m
1.0 m
10 m
100 m
1,000 m
10,000 m
FaF97