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 125.
The exam period was 90 minutes; the mean score was 79.2 the median was
79. 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) = 10+9.
A circuit consists of a 6 V battery, 3 resistors and 2 capacitors as
depicted below. Both capacitors are initially uncharged. Switch
S1 is then closed at time t = 0. Switch S2
remains open until stated otherwise.
What is the voltage V1 across C1
right when S1 is closed (at t = 0)?
(a) V1 = 0 V
(b) V1 = 2 V
(c) V1 = 4 V
(a) P = 0 W
(b) P = 0.12 W
(c) P = 0.24 W
(d) P = 0.72 W
(e) P = 1.2 W
(a) I3 = 0 A
(b) I3 = 0.3 A
(c) I3 = 0.6 A
(d) I3 = 0.8 A
(e) I3 = 1.6 A
(a) C2 = 2 μF
(b) C2 = 3 μF
(c) C2 = 4 μF
(d) C2 = 6 μF
(e) C2 = 12 μF
What is the equivalent resistance Req of the circuit?
(a) Req = 5R/6
(b) Req = 7R/6
(c) Req = 6R/5
(d) Req = 36R/13
(e) Req = 5R
(a) ΔV = 4 V
(b) ΔV = 4.8 V
(c) ΔV = 8 V
A circuit consists of a battery, a capacitor and two resistors in the
configuration shown below. Initially, the switch is open and the
capacitor is uncharged. The values associated with the parameters of
the circuit are ε = 12 V, C = 3 μF,
R1 = 22 Ω and R2 = 15 Ω.
The switch is closed and the capacitor is allowed to charge. When
the charge on the capacitor reaches 10 μC, what is the current
I1 through R1?
(a) I1 = 0.00 A
(b) I1 = 0.15 A
(c) I1 = 0.22 A
(d) I1 = 0.32 A
(e) I1 = 0.39 A
(a) I2 = 0.023 A
(b) I2 = 0.32 A
(c) I2 = 1.20 A
(d) I2 = 1.67 A
(e) I2 = 3.10 A
You are given a circuit consisting of five capacitors and a battery,
What is the total equivalent capacitance Ceq of the
(a) Ceq = 1.7 μF
(b) Ceq = 7.6 μF
(c) Ceq = 12.8 μF
(a) Q3 = 12.7 μC
(b) Q3 = 18.3 μC
(c) Q3 = 27.5 μC
(d) Q3 = 31.8 μC
(e) Q3 = 45.8 μC
Four charges are placed at the corners of a rectangle with sides
of length 3 cm and 4 cm as shown below.
What is the direction of the electric field at the center of the
rectangle due to these charges?
(a) in the +x direction
(b) in the +y direction
(c) in the -y direction
(a) |E| = 2.56 × 105 N/C
(b) |E| = 34.6 × 106 N/C
(c) |E| = 1.38 × 108 N/C
(d) |E| = 2.93 × 109 N/C
(e) |E| = 16.5 × 109 N/C
(a) Wtotal = 0 J
(b) Wtotal = 10 J
(c) Wtotal = 30 J
(d) Wtotal = 45.5 J
(e) Wtotal = 125 J
(a) Wfield = 3.20 × 10-19 J
(b) Wfield = 0.75 × 10-19 J
(c) Wfield = 0 J
(d) Wfield = -3.88 × 10-17 J
(e) Wfield = -5.23 × 10-17 J
(a) Ceq = 4 C0
(b) Ceq = 4 C0 / 3
(c) Ceq = 3 C0 / 4
(d) Ceq = C0 / 4
(e) none of the above
A fixed, conducting sphere A has a net positive charge.
A second conducting sphere B that hangs from the ceiling is placed to
the right of the fixed sphere A, as shown in the figure. Sphere B has
NO net charge. Assume the spheres are ideal conductors.
The electric force between spheres A and B is
This is a map of equipotential lines for two charges
Q1 and Q2. Potential values are
accurate and given in volts.
Which one of the following statements about the magnitudes of the
charges is true?
(a) |Q1| > |Q2|
(b) |Q1| = |Q2|
(c) |Q1| < |Q2|
(e) pointing towards charge Q2
(a) ΔU = -2 μJ
(b) ΔU = 0 μJ
(c) ΔU = 2 μJ
A capacitor is composed of two parallel plates of area 5 ×
10- 4m2 separated by a distance 7 ×
10-4m as shown below.
Consider the situation when the capacitor is in isolation and charged
to maximum capacity. The electric field in this situation is 2 ×
What is the charge Q on one of the plates of the capacitor?
(a) Q = 6.89 × 10-12 C
(b) Q = 8.85 × 10-9 C
(c) Q = 4.67 × 10-6 C
(a) accelerates to the right at 0.0025 m/s2.
(b) accelerates to the left at 0.382 m/s2.
(c) remains motionless since it is the equilibrium point.
Now consider a slab of dielectric constant κ =
3.2 inserted in between the plates as shown in situation B above.
Compared to the situation having no dielectric present, how do i) the
voltage V across the plates and ii) the stored potential energy
(a) Both V and U increase.
(b) V increases and U decreases.
(c) V decreases and U increases.
(d) Both V and U decrease.
(e) Both stay the same.
(a) t5 = 2.87 × 10-12 s
(b) t5 = 1.02 × 10-8 s
(c) t5 = 3.51 × 10-4 s
(d) t5 = 1.32 s
(e) t5 = 6.44 × 104 s
Four resistors and two batteries are connected as shown below. The
corresponding resistances and voltages have the values R1
= R2 = R3 = R4
= 2 Ω and ε1 =
ε4= 4 V. Define currents I using the
directions given by the arrows.
When the switch S is in the 'open' position (as shown), what is the
value of the current I23?
(a) I23 = 0.5 A
(b) I23 = 1.33 A
(c) I23 = 6.75 A
(a) ε1 - I1R1 + I2R2 = 0
(b) I1 + I23 - I4 = 0
(c) ε1 - I1R1 + I4R4 - ε4 = 0