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a. For the graph of Ex vs x, draw a graph of V vs x in this
same region of space. Let V=0 at x=0. Label the y-axis with
numbers.
b. Draw a charge distribution whose field and potential in
the x-direction can be represented by these graphs.
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a. For the graph of V vs x, draw a graph of Ex vs x in this
same region of space. Label the y-axis with numbers.
b. Draw a charge distribution whose field and potential in
the x-direction can be represented by these graphs.
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2
For each contour map, estimate the magnitude
and direction of the electric fields at points 1 and 2
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What is the total potential difference (voltage) created
by these three batteries?
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What is the total potential difference (voltage) created
by these three batteries?
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A capacitor with plates separated by a distance d is charged to
a potential difference, ∆Vc. All wires and batteries are
disconnected, then the two plates are pulled apart (with
insulated handles) to a new separation distance of 2d.
• Does the capacitance C change? If so, by how much?
• Does the capacitor charge Q change? If so, by how much?
• Does the electric field strength E change? If so, by how much?
• Does the potential difference ∆Vc change? If so, by how much?
²V
c
before
after
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d
2d
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Rank the equivalent capacitance Ceq of the circuits
below in order from most to least.
#1
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#2
#3
#4
15
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How much energy is stored in a 2.0 µF capacitor
charged to 5000 Volts?
What is the average power dissipation if this 2.0 µF
capacitor is discharged in 10 µs?
∆V = 5000 V
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Inside a conductor
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1. If the electrons in a current-carrying wire
collide with the positive ions more frequently,
does their drift speed increase or decrease?
2. Does an increase in the
collision frequency make
the wire a better conductor
or a worse conductor?
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1. Which direction are the charge carrying
electrons moving?
2. In which direction does the electric field point?
I
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A light bulb is connected to a battery with 1-mmdiameter wires. The bulb is glowing.
1. What is the direction of E at each of the points
shown? (The points are inside the wire)
2. Rank the electric field strengths at 1, 2 and 3.

3. Where is the current
largest?
1
•
•2
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•3
23
Below is a segment of a circuit. All wires in this
segment are made of the same material and
have the same thickness.
Rank, in order from largest to smallest, the
currents.
I1
I2
I3
I4
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If a metal is heated, does its conductivity
increase, decrease or stay the same? Explain.
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Wire 1 and wire 2 are made from the same
metal. Wire 1 has twice the diameter and half
the electric field of wire 2.
1. Which wire has a greater current density, J?
2. What is the ratio I1/I2?
3. Which wire has a larger electron drift speed?
E2
E1
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A wire consists of two equal diameter segments
of different materials, with 2>1. The current
in segment 1 is I1.
1. Which is larger: I1 or I2?
2. Which is larger: J1 or J2?
3. Which is larger: E1 or E2?
I1
1
2
I2
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