Type:
Single
Date:_________
Objective:
Electrostatics Review
Homework:
Study for Test #11: Electrostatics
AP Physics
Mr. Mirro
Date ___________
Electrostatics Review
1) Two point charges experience a force of repulsion equal to 3 x 10-4 N when separated by 0.40 m. If one of the
charges is 5 x 10-4 C, what is the magnitude of the other charge ?
a) 1.07 x 10-11 C
d) 5.00 x 10-4 C
b) 2.70 x 10-11 C
e)
c) 3.20 x 10-9 C
0C
2) If the electric field does negative work on a negative charge as the charge undergoes a displacement from Position A
to Position B within an electric field, then the electric potential energy
a)
b)
c)
d)
e)
is negative
is positive
increases
decreases
cannot be determined
3) A charge q experiences a displacement within an electric field from Position A to Position B. The change in the
electrical potential energy is ΔUE, and the work done by the electric field during this displacement is WE. Then
a) VB – VA = WE/q
b) VA – VB = q WE
c) VB – VA = q WE
B
B
B
d) VA – VB = ΔUE/q
B
e) VB – VA = ΔUE/q
B
4) Which points in this uniform electric field, between the plates of the capacitor as shown, lie on the same equipotential
line ?
a)
b)
c)
d)
e)
1 and 2 only
1 and 3 only
2 and 4 only
3 and 4 only
1, 2, 3 and 4 all lie on
the same equipotential
+Q
1
4
2
3
-Q
5) How much work would the electric field created by the stationary charge Q perform as a charge q = -0.05 C is
moved from Point A to Point B along the curved path shown, if that path is 0.20 m long ?
a) -10 J
b) -5 J
B
VB = 100 v
q
c) +5 J
RAB = 0.10 m
d) +10 J
e) +20 J
Q
A
VA = 200 v
6) Let Q = 2 x 10-9 C. What is the potential at a Point P that is 2 cm from Q ?
a) 300 v
b) 600 v
c) 900 v
d) 1200 v
e) 1500 v
7) A positive charge +q moves from Position A to Position B in a uniform electric field E. Which expression best
represents the change in electrical potential energy ?
a) ΔUE = -qEr
b) ΔUE = -Er
c) ΔUE = +Er
d) ΔUE = +qr
e) ΔUE = -qr
8) If charges q1 = 4 x 10-9 C and q2 = -6 x 10-9 C are stationary, calculate the potential at Point A in the diagram.
a)
b)
c)
d)
e)
0v
+1080 v
+2520 v
-1080 v
-2520 v
A
3 cm
q1
q2
4 cm
9) Which of the following diagrams represents the equipotential curves in the region between a positive point charge and
a negatively charged parallel plate ?
a)
b)
c)
d)
10) The plates of a parallel plate capacitor are separated by a distance of two millimeters and each has an area
of 0.001 m2. If a layer of polystyrene (κ = 2.6) is sandwiched between the plates, determine the value of
the capacitance.
a) 1.2 x 10-11 F
b) 1.2 x 10-10 F
c) 1.2 x 10-12 F
d) 2.4 x 10-11 F
e) 3.6 x 10-11 F
11. An electron enters a uniform electric field, near the top between two parallel plates vertically separated having electric
field intensity E = 400 N/C. The electron enters with an initial velocity of 4 x 107 m/s. If the length of each plate is
0.15 m,
a. What is the vertical acceleration of the electron ?
e
-
-
-
-
-
-
+
+
+
+
+
+
-
b. How long does the electron travel through
the electric field ?
c. Since the electron enters the field level with the top plate, which is negatively charged, what is
the vertical displacement of the electron during that time ?
d. What is the magnitude of the velocity of the electron as it exits the field ?
-
-
-
-
-
-
+
+
+
+
+
+
e. Sketch the electric field E on the diagram to the right.
12. A charge Q1 = - 16 x 10-6 coulomb is fixed on the x-axis at +4.0 meters, and a charge Q2 = + 9 x 10-6 coulomb is fixed
on the y-axis at + 3.0 meters, as shown on the diagram.
a.
Calculate the magnitude of the electric field E1 at
the origin O due to charge Q1.
b.
Calculate the magnitude of the electric field E2 at
the origin O due to charge Q2.
c.
On the axes below, draw and label vectors to show
the electric fields E1 and E2 due to each charge, and
also indicate the resultant electric field E at the origin.
d.
Calculate the electric potential V at the origin.
e.
A charge Q3 = -4 x 10-6 coulomb is brought from a very distant point (∝) by an external force and placed at the
origin. Calculate the work that had to be done by the external force to bring Q3 to the origin from the distant
point.