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 minutes; the mean was 76.0; the median was 78.
Click here to see page1
page2 of the formula sheet that came
with the exam.
(a) The charge on C1 decreases.
(b) The charge on C1 stays the same.
(c) The charge on C1 increases.
(a) (14/3) R
(b) 4 R
(c) (7/5) R
(d) (4/3) R
(e) (2/5) R
With the switch open as shown, what is the current
(a) I1 = -7/2 A
(b) I1 = -1/2 A
(c) I1 = 1/2 A
(d) I1 = 3/2 A
(e) I1 = 7/2 A
What is the voltage across the 4 ohm resistor?
(a) 6 V
(b) 8 V
(c) 14 V
(d) 2 V
(e) 7 V
(a) Only I3 has changed in magnitude.
(b) Only I2 and I3 have changed in magnitude.
(c) I1, I2 and I3 have all changed in magnitude.
(a) Rtot,1 > Rtot,2
(b) Rtot,1 < Rtot,2
(c) Rtot,1 = Rtot,2
At time t = 0 the switch is closed with the capacitor
uncharged. The current through the capacitor right after the switch is
closed is 0.0343 A.
What is the initial current through the 100 Ω resistor right after
the switch is closed?
(a) 0.103 A
(b) 0.069 A
(c) 0.048 A
(a) 2.4 × 10-5 C
(b) 4.8 × 10-5 C
(c) 6.2 × 10-5 C
(d) 7.2 × 10-5 C
(e) 8.6 × 10-5 C
(a) 1.4 × 10-3 s
(b) 1.5 × 10-3 s
(c) 1.8 × 10-4 s
(a) 1.4 × 10-3 s
(b) 1.5 × 10-3 s
(c) 1.8 × 10-3 s
A square one-turn loop (side a = 20 cm, resistance R =
5 Ω, mass m = 200 g) located in the xy plane coasts
with initial velocity v0 = 10 m/s in the
x-y plane parallel to the x-axis in a region of no
magnetic field as shown in the diagram. At time t = 0 s the loop
enters a region of constant uniform magnetic field B = 1.5 T
directed in the -z direction (into the page). In the following
questions neglect any effect of magnetic fields that might be created by
an induced current in the loop.
What is the magnitude of the EMF induced in the loop just after
it enters the field? (Remember 1 mV = 10-3V).
(a) EMF = 150 mV
(b) EMF = 750 mV
(c) EMF = 3 V
(a) F = 4 a B v R
(b) F = a2 B v R
(c) F = a2 B2 v R
(d) F = a2 B2 v / R
(e) F = a2 B2 v2 / R
A tightly wound circular coil with radius a = 3 cm and
N = 150 turns lies parallel to the x-y plane. The
total resistance of the coil is 5 Ω. A spatially uniform magnetic
field extends over the entire region of the coil and points in the
+z direction (out of the page). The magnitude of the field
varies with time as shown below (the maximum field B0
= 2 T is obtained at time t2 = 10 seconds). Neglect
the effect of any B fields that might be created in the coil.
In what direction is the induced current flowing at time
t1 = 5 seconds?
(a) I1 < I3
(b) I1 = I3
(c) I1 > I3
(a) I1 = 12 mA
(b) I1 = 17 mA
(c) I1 = 38 mA
(d) I1 = 52 mA
(e) I1 = 85 mA
A generator consisting of a single loop of wire with area A is
used to light a bulb with resistance R. The coil is rotated with
constant angular velocity ω.
At which angle θ (as defined in the figure) is the flux through
the loop largest?
(a) θ = 0°
(b) θ = 45°
(c) θ = 90°
An infinitely long wire carries a current Iw = 3.0
A (out of the page), and lies along the axis of symmetry of a
cylindrical shell of inner radius a = 2.70 cm and outer radius
b = 7.60 cm. The shell carries a current I2 = 1.8 A
(into the page) distributed with uniform current density J.
Find the magnetic field strength at a distance r = 2.00 cm
from the wire.
(a) B = 0
(b) B = 1.2 × 10-5 T
(c) B = 1.8 × 10-5 T
(d) B = 3.0 × 10-5 T
(e) B = 4.8 × 10+5 T
(a) B = 2.9 × 10-6 T
(b) B = 6.7 × 10-6 T
(c) B = 8.2 × 10-6 T
(a) B = 2.7 × 10-6 T
(b) B = 4.0 × 10-6 T
(c) B = 0
An infinitely long wire carries a current I1 = 23
A. Another wire in the shape of a rectangular loop with sides a =
0.09 m and b = 0.20 m carries a current I2 = 15
A, and is placed near the infinitely long wire as shown in the figure
below. (The side of the loop closest to the wire is a distance x
= 0.01 m away from it.)
Calculate the z component of the magnetic field at the center of
the rectangular loop (point P) due to the infinitely long wire.
(c) There is no direction since F = 0.
(a) emerge at the same position X, but after a different amount of
(b) emerge at a different position X, but after the same amount of time
(c) emerge at a different position X and after a different amount of time