Unit: Electricity and Magnetism
Why discussed together?
Highly related!
Unit: Electricity and Magnetism
• Electric Fields
• Electric Potential
•
•
•
Capacitance and Dielectrics
Current and Resistance
DC Circuits
• Magnetic Fields
•
Sources of…
• Faraday’s Law
•
•
Inductance
AC Circuits
James Clerk Maxwell
• Put it all together: Electromagnetic Waves
The charge on a ball is measured to be
3.2 x 10-14 C.
a) Does the ball have more or less
electrons than protons?
b) How many more or less?
A positively charged ball is brought near a long
piece of aluminum, as shown. Draw the
aluminum and note the positions of the greatest
and least number of electrons.
Three identical uncharged balls are connected
by conducting wires as shown. A charge of 4Q is
induced into the top ball. Give the magnitude
and direction of the force that the left ball now
exerts on the right ball (in terms of d and Q)?
d
Two conducting spheres are held a distance d
apart as shown. What is force of one on the
other?
Q
3Q
d
Two conducting spheres are held a distance d
apart as shown. What will be the force of one on
the other after they are connected by a wire?
Q
3Q
d
Three charges are arranged along a line as shown in
the figure below. The sizes of the charges and the
distances are not to scale.
If d1 = d and d2 = 3d, while Q1 = Q and Q3 = 4Q, then
1. |FQ1→Q2 | > FQ3→Q2
2. |FQ1→Q2 | < FQ3→Q2
3. |FQ1→Q2 | = FQ3→Q2
4. You cannot tell without knowing Q2.
There are four one-dimensional arrangements of
charges. Each charge has the same magnitude
but they differ in sign. In which of the diagrams
would the magnitude of the force felt by a
positive test charge placed at P be the largest?
1.
2.
3.
4.
A
B
C
D
5.
6.
7.
8.
9.
A and B
A and C
C and D
All are equal
Can’t tell
In the figure there are 4 two-dimensional
arrangements of positive and negative charges.
In which of the diagrams would the magnitude
of the force felt by a positive test charge placed
at P be the largest?
1.
2.
3.
4.
A
B
C
D
5.
6.
7.
8.
9.
A and B
A and C
C and D
All are equal
Can’t tell
Problem:
Three charged balls are shown below. The ball
containing a charge of +Q is free to move, but
the others are fixed. Where should an additional
ball containing charge -2Q be placed in order to
keep the +Q ball stationary?
+Q
3Q
-Q