Spring 2013
Liam Brown, Tutor
c.liam.brown@gmail.com
McGill PHYS 102
TOTALLY UNOFFICIAL
Practice Midterm
Please note that this midterm was written by a tutor with no official connection to McGill University.
Thus, it is not necessarily representative of the length, format, difficulty, or content of any part of the
actual PHYS 102 final exam.
Estimated length: 2 hours (or maybe more)
Allowed equipment:
 Non-programmable calculator
 Writing utensil(s)
 Drinking water
 Non-programmable helper animal
Page 1 of 5
UNOFFICIAL McGill PHYS 102 Practice Midterm – Spring 2013
Liam Brown, tutor – c.liam.brown@gmail.com
Page 2 of 5
Question 1
In the diagram at right, four charges of equal magnitude (±75 μC) are held
in place at the corners of a square with sides of length L = 36 cm. Point B is
at the center of the square.
a)
What is the magnitude and direction of the electric field at
point B?
b) Which is an equipotential line: AB or
answer – no calculations required.)
c)
BC ? (Brief sentence
A +30 μC charge of mass 91 g is released from rest at point B. At
what speed is it travelling when it reaches point A?
UNOFFICIAL McGill PHYS 102 Practice Midterm – Spring 2013
Liam Brown, tutor – c.liam.brown@gmail.com
Page 3 of 5
Question 2
A circuit is assembled as shown at right.
a)
The 30 Ω resistor is cylindrical, 1.0 cm long, and made of
a material with resistivity ρ = 0.15 Ωm. What is its
diameter?
b) What is the magnitude of the current through the 30 Ω
resistor?
c)
How much power is drawn by the 7 V battery?
UNOFFICIAL McGill PHYS 102 Practice Midterm – Spring 2013
Liam Brown, tutor – c.liam.brown@gmail.com
Page 4 of 5
Question 3
Five identical 40 μF capacitors are connected as shown.
a)
What is the equivalent capacitance of this
arrangement?
b) The two free ends are connected to a 12 V battery. Once all of the capacitors are charged, what is the
charge on C4?
c)
C1 is removed from the circuit. A dielectric with κ = 1.43 is inserted into it, and the separation distance
between its two plates is doubled. What is its new capacitance?
UNOFFICIAL McGill PHYS 102 Practice Midterm – Spring 2013
Liam Brown, tutor – c.liam.brown@gmail.com
Page 5 of 5