Download Electric Field Lines I

Electric Field Lines I
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Electric Field Determined from Equal-Potential Plots
1. If you wanted to know the slope of the curved line at r = 2.5m, would the straight line
connecting the points r = 2 and r = 3 be a good approximation? ___________
2. If only using the discrete data points (not the curve) could you estimate the slope at
r = 3 as accurately as at r = 2.5m using the same points you used above __________
Explain.
3. Estimate the slope of the straight line you drew in Q1. Show your calculation, Box
answer and units.
4. Calculate the slope in a similar manner for the r interval [1, 2]. Show your calculation,
Box answer and units.
5. Calculate the slope in a similar manner for the r interval [3, 4]. Show your calculation,
Box answer and units.
6. Calculate the slope in a similar manner for the r interval [4, 5]. Show your calculation,
Box answer and units.
7. Calculate the slope in a similar manner for the r interval [5, 6]. Show your calculation,
Box answer and units.
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8. Turn to the Equal-Potential Lines plot. This plot represents the same data from the first
graph in a different manner. Using the formula E = V/r, calculate the electric field for
the [0, 10V] interval. Show work. Box answer and units.
9. Referring to the previous graph and your analysis, at what value of r is the slope you
calculated in Q8 most likely to match the real data (refer to the V vs. r graph line)?
Most likely r =___________
10. Using the formula E = V/r, calculate the electric field for the [10V, 20V] interval.
Show work. Box answer and units.
11. Using the formula E = V/r, calculate the electric field for the [20V, 30V] interval.
Show work. Box answer and units.
12. Using the formula E = V/r, calculate the electric field for the [70V, 80V] interval.
Show work. Box answer and units.
13. Refer to the V vs. r graph. Should the answer to Q12 be similar the answer to
Q7?_______ Explain.
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Graphs
100
90
80
70
V(volts)
60
50
40
30
20
10
0
1
2
3
4
5
6
r(meters)
0V
90
10 V
20V
30 V
40 V
5
0
6
0
7
0
8
0
80
70
60
50
40
30
20
10
0
1
2
3
4
5
6
r(meters)
3