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 115.
The exam period was 90 minutes; the mean score was 87.8; the median was
90. Click here to see page1
page3 of the formula sheet that came
with the exam.
Some helpful information: • 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) =
A proton enters a magnetic field of magnitude 4.7 T directed into the
page. When an external electric field of 300 N/C, directed downward, is
applied, the proton travels in a straight line.
What is the speed of the proton?
(a) 1.2 ×10-2 m/s
(b) 3.5 m/s
(c) 47.0 m/s
(d) 63.8 m/s
(e) 126 m/s
(a) 1.24 × 10-5 T out of the page
(b) 4.10 × 10-5 T out of the page
(c) 8.10 × 10-5 T out of the page
(d) 4.10 × 10-5 T into the page
(e) 1.24 × 10-5 T into the page
A rectangular loop of sides a = 6.75 cm and b = 12 cm
is sitting in a magnetic field of strength B = 5 mT, as shown in
the diagram. A current of 6 A flows through the loop. The normal to
the loop makes an angle of 70° with respect to the magnetic field.
Calculate the torque on the loop.
(a) τ =1.88 × 10-4 Nm
(b) τ = 2.28 × 10-4 Nm
(c) τ = 2.43 × 10-4 Nm
(a) B = 0.004 T
(b) B = 0.012 T
(c) B = 0.049 T
(d) B = 0.121 T
(e) B = 0.367 T
(a) When the flux through the loop is at a maximum, the induced EMF is zero.
(b) When the flux through the loop is zero, the induced EMF is zero.
(c) The induced EMF does not depend on the area of the loop.
Which one of the following statements is FALSE?
(a) The current in the loop switches directions after a period of time.
(b) The induced EMF in the loop is never zero.
(c) The magnetic field through the loop is always increasing.
A solenoid has a diameter of 1 cm and a length of 20 cm. If it has
an inductance of 3 μH, how many loops of wire make up this
(a) 6.0 × 10-12 J
(b) 7.8 × 10-11 J
(c) 1.4 × 10-10 J
A rectangular coil of dimensions 4 cm x 3 cm and with 20 turns is
being pulled into and through a region of uniform magnetic field of 2 T
at a speed of 3 m/s.
Just after the left side of the coil enters the magnetic field
region, what is the magnitude of the induced EMF?
(a) 0 V
(b) 0.34 V
(c) 0.0024 V
(d) 3.6 V
(e) 4.8 V
(a) There is no current.
In the RLC circuit shown above, a function generator provides an AC
voltage of amplitude V0 = 120 V at a frequency
f = 60 Hz. The components in the circuit have values R =
30.0 Ω, L = 200 mH and C = 20.0 μF.
What is the phase angle between the current and the AC source?
(a) 0.400 A
(b) 0.571 A
(c) 0.929 A
(d) 1.06 A
(e) 1.86 A
(a) 1.22 μF
(b) 5.41 μF
(c) 11.2 μF
(d) 35.2 μF
(e) 48.0 μF
(a) 50 W
(b) 120 W
(c) 180 W
(d) 240 W
(e) 300 W
(a) in DC circuits only
(b) only when the current is at its maximum value
(c) in all circuits at every instance of time
Consider a circular conducting loop of diameter d = 10 cm
placed in a uniform magnetic field B. The magnetic field
B(t) changes in time as shown in the plot to the right.
Note: in this plot, a positive value for B(t)
corresponds to a field directed into the page.
What is the direction of the current around the loop at time t
= 5 s?
(a) 0 mV
(b) 0.78 mV
(c) 1.45 mV
(d) 20.6 mV
(e) 643 mV
(a) t = 5 s
(b) t = 12 s
(c) t = 20 s
A rectangular loop of sides a = 2 cm and b = 3 cm has
N = 32 turns. The loop carries a current of 2.7 A. The surface
normal makes an angle θ with the z-axis. A uniform
external magnetic field of B = 2.0 tesla points in the positive z
direction. The torque on the loop is 0.072 Nm. Calculate the angle
(a) τsquare / τrectangle = 0.82
(b) τsquare / τrectangle = 1.00
(c) τsquare / τrectangle = 1.22
A beam of particles with same mass m and same velocity
v = 9000 m/s but with different charges q1,
q2 and q3 is sent into a uniform
magnetic field B = 0.8 T that is pointing out of the page. The
situation is sketched here.
The magnetic field does a larger work on charge q2
than on charge q1.
(a) q1 > q2 > q3
(b) q2 > q1 > q3
(c) q3 > q1 > q2
(a) 1.67 × 10-27 kg
(b) 2.94 × 10-26 kg
(c) 3.69 × 10-26 kg