Midterm—Physics 204-1R
Name___________________________
1. (5 pts) Draw 6 electric field and 6 equipotential lines for this configuration of charges. For each, let
the field and equipotential lines span the entire region within the rectangle. For the second
configuration of charges, show how the charges are distributed on the sphere in the middle.
3. (15 pts) Given this data for a particular circuit consisting of a resistor in series with a power supply,
determine (graphically) the voltage provided by the power supply.
R ( ohms)
1
2.4
3.2
5.4
8
11
I (amps)
3.8
1.6
1.3
0.9
0.4
0.3
V=______________
4. (15 pts) This graph shows voltage versus length for a slide wire like you used in lab. The current
was kept constant at 2 A to collect this data. Determine the resistivity of the wire.
The cross-sectional area of the wire is 2x10-6 m2.
6. (10 pts) Consider the following circuit. What is the equivalent resistance? What is the potential
across each resistor? What is the current through each resistor?
Req=_____________
V1= _____________
V2= _____________
V3= _____________
I1= _____________
I2= _____________
I3= _____________
7. (5 pts) Describe how a voltmeter is constructed:
8. (5 pts) For the two following scenarios, sketch an ammeter or voltmeter on the figure as directed.
Use the following symbols for ammeter and voltmeter:
Ammeter:
Voltmeter:
a) Show, in this figure, how you would hook up an ammeter to measure the current in R1.
b) Show how you would hook up a voltmeter to measure the voltage across R2.
9. (5 pts) The following figure shows an ammeter whose full swing current (Ifs) is normally 1 Amp.
The ammeter has a shunt resistor added to increase its range; the currents are as shown on the figure.
By what factor has the range of the ammeter been increased?
10. (10 pts) This figure shows a Wheatstone Bridge. Derive the equation for the unknown resistance
Rx. Show all steps.
11. (5 pts) What is the equivalent resistance of this circuit?