Download Electric Charge, Coulomb`s Law, Electric Fields, Field Lines, Electric

Review of Electric Charge, Coulomb’s Law, Electric Fields, Field Lines,
Electric Potential and Electric Energy
Name:
Blk:
1.
a) What is static electricity?
b) What is the law of conservation of electric charge?
c) Describe the charge distribution of an atom.
d) What property of a conductor makes it different from an insulator.
e) Explain how induced charge is different from charging by contact. Use a diagram to show the
difference.
2.
Explain what Coulomb’s law is.
3.
Use the diagram at the right to answer the
following questions. scale 1cm = 1m
a) What is the net force applied on the 7 by the
two negative charges?
b) What is the net force applied on the 7  C by all
charges?
c) If the 7  C were free to move, what electric
-10C
force would have to be applied to it such that it
remain stationary?
d) In order to accomplish part C above, a positive
charge is placed at a distance of one meter from
the 7  C charge. What magnitude should the
positive charge have and where should it be placed?
4.
Fk
5.
5C
-3 C
7 C
3C
Use words and diagrams to describe the meaning and the difference between each of the following
equations.
Q1Q2
r2
Ek
Q
r2
An electron and a proton are separated by a distance of 2.5 m. If another proton is placed into
the electric field of these two charges such that the relationship between them is like in the diagram
below, then:
a) calculate the direction of the electric field at the point where the proton is placed.
b) calculate the magnitude and direction of the net force on the introduced proton.
proton
0.7 m
2.5 m
electron
Tolksdorff
proton
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6.
What is the counterpart to voltage when talking about gravitation?
7.
Here you will compare gravity against electricity.
a)
How does the Earth’s gravitational field change
with distance?
b) How does the Earth’s gravitational potential
change with distance?
c)
Near the Earth, PE = mgd
d) PE/m =gd
8.
a)
How does a charge’s electric field change with
distance?
b) How does a charge’s electric potential change
with distance?
c)
In a uniform electric field, PE = _________
d) PE/q = V = ________
Explain the difference between the following two equations. What is the fundamental difference in
the application of each equation? Use diagrams to show the difference.
V  Ed
V k
Q
r
9.
Two parallel plates are charged to 12 V. If the separation between the plates is 0.02m, calculate
the potential energy gained by an electron forced from the positive plate to the negative plate.
Draw a diagram of the situation.
10.
A 5C charge is moved toward a 15 C charge. When 3 J of work are applied they end up at a
distance of 0.005m apart. How far apart were the charges before the work was done?
11.
An electron is accelerated by a potential difference of 100V. How much greater will its final speed
be if it were accelerated with four times the voltage?
12.
If a negative charge is initially at rest in an electric field, will it move toward a region of higher
potential or lower potential? What about a positive charge? How does the potential energy of
each charge change in each case?
13.
a) What do the circles in the diagram at the
right represent?
b) What is the electric potential difference
between points x and y in the diagram at the
right?
c) What is the least amount of work that must
be done to move a proton from x to y?
x
1.7 µC
R = 15 cm
r = 5 cm
y
Tolksdorff
Review Electrostatics and Electric Potential
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