True-false questions are worth 2 points each, three-choice multiple
choice questions are worth 3 points each, five-choice multiple choice
questions are worth 6 points each. The maximum possible score is 100.
The exam period was 90 minutess; the mean score was 66.4; the median was
67. Click here to see page1
page2 of the formula sheet that came
with the exam.
Some helpful information:
• A physics 102 light bulb acts just like a resistor: its resistance
is constant, independent of the current flowing through the light bulb.
The bulb's brightness increases with increasing current.
• A reminder about prefixes: p (pico) = 10-12; n (nano) =
10-9; μ (micro) = 10-6; m (milli) =
10-3; k (kilo) = 10+3; M or Meg (mega) =
10+6; G or Gig (giga) = 10+9.
What is the maximum voltage produced across the resistor by the coil?
(a) 20 mV
(b) 50 mV
(c) 240 mV
V(t) = 480 sin(ωt)
(a) 480 V
(b) 339.4 V
(c) 240 V
A solenoid of length 0.5 m and radius
.03 m is wound with 1000
What is the inductance of this solenoid?
(a) 7.1 mH
(b) 3.55 mH
(c) 14.2 μH
(a) 1.88 mT
(b) 2.5 mT
(c) 3.77 mT
(c) not changed.
The phasor diagram at the left corresponds to a series
RCL circuit driven by a sine wave generator with maximum
voltage of 30 V. The magnitudes of R, XL
and XC are labeled on the phasor
What is the magnitude of the total impedance Z of the
(a) 190 Ω
(b) 50 Ω
(c) 70 Ω
(a) 18 V
(b) 30 V
(c) 15 V
(d) 25 V
(e) 10 V
The phase angle Φ describes the phase relationship between the
voltage supplied by the signal generator, V(t) =
Φ), and the current that flows in the circuit,
is the phase angle at frequency f = 600 Hz ?
(a) 56.9° (= 0.993 radians)
(b) -56.9° (= -0.993 radians)
(c) 27° (= 0.471 radians)
(d) -27° (= -0.471 radians)
(e) 35.5° (= 0.620 radians)
(a) 600 W
(b) 543.8 W
(c) 300 W
A conducting metal band containing a 5
Ω resistor is formed into a circle of radius
R as shown in the diagram. The band runs through a
computer-controlled motorized screw-drive so that the circumference of
the band changes as the screw-drive turns, changing the size of the
circle smoothly as dictated by the computer. The circle always lies in
the plane of the paper, perpendicular to a uniform magnetic field
B of 0.25 T.
The computer-controlled screw drive turns so as to
decrease the circumference of the loop. Because of
(a) a current that flows clockwise is induced in the loop.
(b) a current that flows counterclockwise is induced in the loop.
(a) 50 mA
(b) 35 mA
(c) 10 mA
(d) 5 mA
(e) 1 mA
The magnitude of the current induced in the loop is greatest at which
of the following times?
(a) t = 0.5
(b) t = 1.0
(c) t = 1.5
A transformer with a 100-turn primary coil and
300-turn secondary coil is wired to a signal generator and
50 Ω resistor as shown in the
following diagram. The signal generator produces a 60 Hz
The signal generator's peak voltage is 24
volts. How much peak power is delivered to the resistor
attached to the transformer's secondary?
(a) 11.52 W
(b) 72 W
(c) 103.68 W
(d) 1200 W
(e) 15000 W
(a) Psignal generator / Presistor = 0.25
(b) Psignal generator / Presistor = 1
(c) Psignal generator / Presistor = 4
A generator is built by winding 30 turns around a
circular form of radius 0.1 m and then attaching it to a
horizontal motor-driven shaft as shown in the figure below. The loop
rotates in a uniform vertical magnetic field of strength B =
0.3 T; the wire of the loop is somewhat resistive so that the total
resistance of the 30 loops is 4
Ω. The angle Φ between
the normal to the loop and the magnetic field obeys the equation
Φ = 75t radians. (This means that
ω = 2πf = 75 radians/second.)
At the time t shown in the diagram, Φ
= π/2 radians = 90°.
When the orientation of the loop is as shown in the figure, the
flux of magnetic field through the loop is at its maximum
An American traveller with an electric razor enters a hardware store
in Toledo hoping to buy a transformer to convert 110 V, 50
Hz power into U.S. standard 110 V, 60 Hz power.
He describes his problem to the proprietor and asks for help. The owner
of the hardware store explains that he should buy
(a) a transformer whose primary has 1.2 times as many windings as its secondary.
(b) a transformer whose secondary has 1.2 times as many windings as its primary.
(c) razor blades and shaving cream since transformers convert voltage, but not frequency
You are trying to make isotopically pure Uranium235 to
sell on the black market. You have a mixture of
U235 and U238 which
you are trying to separate by ionizing it and passing it through a
region with uniform 1.5 T magnetic field, after which the
ions strike a screen. The masses of the two isotopes are
M238 = 3.95 ×
10-25 kg and M235 = 3.90
× 10-25 kg. The
ions are all singly ionized so they have charge q235 =
q238 = +1.6 ×
10-19 C. All ions have the same velocity, as shown,
of v = 100 m/s. The magnetic field is into the
Which of the two isotopes strikes higher on the screen?
(a) 60.25 T
(b) 6.25 T
(c) 0.625 T
(d) 0.0625 T
(e) 0.00625 T
(a) π / 2
(b) 2 π
(c) 1 / 2
A particle of charge q = -3
μC is traveling with speed
v = 50 m/s in a uniform field B = 4 T, as
shown. θ =
What is the force on the particle?
(a) 55.4 μN out of the page
(b) 230 μN into the page
(c) 230 μN out of the page
(d) 554 μN into the page
(e) 23.0 μN into the page
(a) a helix.
(b) a circle oriented in the plane of the page.
(c) a circle oriented perpendicular to the page.
A square, horizontal loop with side length L = 0.1
m is attached to a pivot around which it may freely rotate. A
magnetic field B = 0.5 T is applied parallel to the plane
of the loop, as shown. A battery (not shown) forces a constant current
to flow around the loop.
Because of the torque exerted by the magnetic
field, the loop would begin to rotate were it not for a mass m = 1
kg suspended from one side of the loop. Recall that g =
9.8 m/s2. †
Which way must the current flow in the loop to keep it from rotating due to the weight of the mass?
(a) as indicated by the arrow marked "A"
(b) as indicated by the arrow marked "B"
(a) 196 A
(b) 98 A
(c) 49 A
(d) 24.5 A
(e) 12.25 A
A two-loop circuit is attached to a rotating pivot and suspended in a
uniform magnetic field, B, pointing to the
right. R = 1 Ω, V
= 10 V, B = 1 T , and L = 1 m.
Initially the switch S is closed. In which direction
will the loop turn? (Refer to the arrows drawn around the pivot.)
(a) as indicated by arrow A
(b) as indicated by arrow B
(c) The loop will not turn.
(a) 0.1 N-m
(b) 0.5 N-m
(c) 1 N-m
(d) 5 N-m
(e) 10 N-m