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PES 112 General Physics II
Practice Exam 1
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Show all work. Attach additional paper if needed.
If you disagree with all of the available answers, indicate your solution. Provide units where
indicated with ( ).
One (3” x 5”) index card may be used for formulas or other notes or diagrams.
Definitions & Concepts (2 pts each)
1. Equipotentials are lines along which:
a. The electric field is constant in magnitude and direction.
b. The electric charge is constant in magnitude and direction.
c. A charge moving at constant speed requires the maximum amount of work to be done
against electrical forces.
d. A charge may be moved at constant speed without work against electrical forces
e. Charges move by themselves.
2. The electric potential inside a charged solid spherical conductor in equilibrium:
a. Is always zero.
b. Is constant and equal to its value at the surface.
c. Decreases from its value at the surface to a value of zero at the center.
d. Increases from its value at the surface to a value at the center that is a multiple of the
potential at the surface.
e. Is equal to the charge passing through the surface per unit time divided by the
resistance.
3. What units will result from the multiplication of volts times coulombs?
a. Newtons
b. Meters per second
c. Kilograms per meter
d. Joules
Applications (4-6 pts each)
4. If a = 3.0 mm, b = 4.0 mm, Q1 = –60 nC, Q2 = 80 nC, and q = 30 nC in the figure, what is the
magnitude of the total electric force on q?
5. If a = 60 cm, b = 80 cm, Q = –6.0 nC, and q = 6.0 nC, what is the magnitude of the electric
field at point P in the figure?
R. Gist
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Long Semester Ver. B, Rev 1
PES 112 General Physics II
Practice Exam 1
6. An electron enters a region of uniform electric field (E = 50 N/C) with an initial velocity of 40
km/s directed the same as the electric field. What is the speed of the electron 1.5 ns after
entering this region?
7. The total electric flux through a closed cylindrical (length = 1.2 m, diameter = 0.20 m) surface
is equal to —5.0 N ⋅ m2/C. Determine the net charge within the cylinder.
8. Charge of a uniform density (8.0 nC/m2) is distributed over the entire xy plane. A point charge
of 5.0 μC is fixed at z = 1.0 m. Determine both the magnitude of the electric field and the
electric potential for the point midway between the point and the plane.
9. What amount of charge can be placed on a spherical conductor with radius = 1.0 cm, before arc
discharge will occur due to dielectric breakdown of the air?
10. A spherical conductor of radius 5 cm has 6 μC of charge placed on it. A smaller, neutrally
charged conducting sphere of radius 3 cm is attached via a long, thin wire far from the first
sphere. How much charge moves from the large sphere to the small one?
R. Gist
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Long Semester Ver. B, Rev 1
PES 112 General Physics II
Practice Exam 1
11. Three identical point charges (+2.0 nC) are placed at the corners of an equilateral triangle with
sides of 2.0-m length. If the electric potential is taken to be zero at infinity, what is the electric
potential at the midpoint of any one of the sides of the triangle? What is the potential energy
contained in this system due to the three charges?
Types of charged objects that may be used on the exam:
Uniformly charged object
shape
Infinite line of charge with
linear charge density λ
Electric field
Electric Potential
Infinite plane of charge with
surface charge density σ
Point of charge q
Spherical shell of charge
with surface charge density σ
Sphere of solid charge with
charge density ρ
R. Gist
3 of 3
Long Semester Ver. B, Rev 1