This exam consists of 32 questions; 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 112. When the exam was given, the mean
was 89.4; the median was 91. Click here to see page1 page2
of the formula sheet that came with the exam.
A square loop of wire carries a current I. Current is flowing in a
counterclockwise direction as shown.
What is the direction of the magnetic field at A?
(a) into the page
(b) out of the page
(c) the B field is zero
Two square loops of wire are oriented in a uniform magnetic field as
shown. Both loops are attached to and free to rotate about a pivot rod.
The current which flows in each loop is provided by power supplies which
are not shown.
The current in the outer loop is Ib = 5 A. The length of
side b = 0.4 m and the uniform magnetic field strength is B = 2
T. What is the maximum torque on the outer loop?
(a) 0.8 N m
(b) 1.6 N m
(c) 2.4 N m
(d) 3.2 N m
(e) 4.0 N m
(a) left side comes out of the page and the right side goes into the page.
(b) right side comes out of the page and the left side goes into the page.
(a) ta < tb
(b) ta = tb
(c) ta > tb
Two positively charged particles enter a region of uniform
magnetic field B. The B field is oriented perpendicular to the page.
The paths of the two charged particles are shown.
Which direction is the B field pointing?
(a) into the page
(b) out of the page
(a) particle a
(b) particle b
(a) L = 0.33 m
(b) L = 0.50 m
(c) L = 1.50 m
(d) L = 2.67 m
(e) L = 7.50 m
(a) magnet A
(b) magnet B
(c) they hit at the same time
A long solenoid with 3333 turns per meter carries a current in the
direction of the arrow. Its magnitude as a function of time is given by
A rectangular loop with resistance 15 W
surrounds the solenoid.
At time t = 0, the magnetic field at the center of the
(a) B = 0.015 mT
(b) B = 30.1 mT
(c) B = 62.8 mT
(a) into the shown open end.
(b) out of the shown open end.
(a) F = 0.79 × 10-4 T m2
(b) F = 2.26 × 10-4 T m2
(c) F = 4.52 × 10-4 T m2
(a) I = 0.11 × 10-6 A
(b) I = 0.67 × 10-6 A
(c) I = 1.05 × 10-6 A
(d) I = 5.99 × 10-6 A
(e) I = 18.6 × 10-6 A
(a) from A to B.
(b) from B to A.
A long wire carrying a 150 A current is suspended to the ceiling. A
0.3 m wide conducting bar is free to move up or down along two vertical
conducting rails. With a particular current through the bar, it
"floats" 0.005 m below the wire. Its mass per unit length is
What is the magnetic field due to the 150 A current at the location
of the floating bar, 0.005 m below the wire?
(a) B = 6 × 10-3 T
(b) B = 12 × 10-3 T
(c) B = 18 × 10-3 T
(a) I = 1.02 A
(b) I = 8.86 A
(c) I = 22.2 A
(d) I = 40.8 A
(e) I = 62.1 A
(a) to the right (clockwise)
(b) to the left (counter-clockwise)
A mechanical crank is used to turn a rectangular loop with area 0.33
m2 at angular frequency w in the
presence of a magnetic field B = 0.4 T as shown. The 200
V peak EMF produced in the loop results in a peak voltage across the
primary of the transformer of Vp = 200 V. The secondary
windings are connected to an oscilloscope.
What is the peak voltage in the secondary, Vs?
(a) Vs = 66.6 V
(b) Vs = 200 V
(c) Vs = 600 V
(a) F = 0.13 T m2
(b) F = 0.36 T m2
(c) F = 0.40 T m2
(a) T = 2.3 ms
(b) T = 3.6 ms
(c) T = 4.1 ms
(d) T = 7.2 ms
(e) T = 9.8 ms
Two identical conducting loops are moving in a region of uniform
magnetic field (indicated by the X’s). They are moving with equal
speed, but loop number 1 is traveling down and loop number 2 is
traveling to the right.
Compare the magnitude of the induced current in the two loops.
(a) I1 < I2
(b) I1 = I2
(c) I1 > I2
The phasor diagram to the right yields information on a particular
series RLC circuit. It is only partially labeled, but you should
know from examining it the proper quantity that is referred to by each
line in the drawing.
At the instant shown in the diagram, the voltage across the inductor
(a) faster than
(b) slower than
(a) XC = 45 W
(b) XC = 60 W
(c) XC = 125 W
(a) R = 25 W
(b) R = 50 W
(c) R = 75 W
(d) R = 100 W
(e) R = 125 W
(a) Vc = 3.32 volts
(b) Vc = 4.13 volts
(c) Vc = 9.97 volts
(d) Vc = 24.8 volts
(e) Vc = 38.1 volts
(b) remain the same.
A vertically polarized electromagnetic wave is incident on a series
of two linear polarizers as shown below.
If the initial intensity of the incident light is
I0, what is the intensity I2
transmitted by the stack?
(a) I2 = 0
(b) I2 = 0.35 I0
(c) I2 = 0.67 I0
(d) I2 = 0.84 I0
(e) I2 = 0.91 I0
(a) in front of polarizer 1
(b) between polarizers 1 and 2
(c) after polarizer 2
The figure to the right illustrates a plane electromagnetic wave.
Compare the z-component of the electric field at the
points a and b.
(a) Ea > Eb
(b) Ea = Eb
(c) Ea < Eb
(a) towards earth
(b) away from earth