Electric Circuits unit test
A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.
Kilowatt-hour
Measuring resistance experimentally
Resistance and resistivity
Choosing the power form
Ohm's law
Where the energy goes
Meters connected wrongly
Effect of adding a parallel branch
Kirchhoff loop rule
Series vs parallel capacitor voltage
RC circuit charging
Internal resistance is in series
Short answer 1. Define or explain: Ideal ammeter
3 ptsShort answer 2. Define or explain: Brightness in series versus parallel
3 ptsShort answer 3. Define or explain: Why headlights dim when cranking
3 ptsShort answer 4. Define or explain: Resistivity versus resistance
3 ptsFree response
10 ptsStudents are asked to determine the resistivity of the material in a long, uniform wire. They have a battery, an ammeter, a voltmeter, a meterstick, and a micrometer. The cross-sectional area of the wire is measured as 8.0 × 10⁻⁸ m². The students cut samples of different lengths, measure the resistance of each, and record the data below. L (m) 0.20 0.40 0.60 0.80 1.00 R (Ω) 1.1 2.2 3.2 4.3 5.4
A(i). Describe how the students could use the ammeter, voltmeter, and battery to measure the resistance of one wire sample. A(ii). Describe one step that would reduce experimental uncertainty.
B(i). Indicate what quantities the students should graph on the horizontal and vertical axes to obtain a straight line usable to determine the resistivity. B(ii). Describe how the resistivity is related to a feature of that graph.
C(i). Describe the axis labels, with units, and the positions of the plotted points. C(ii). Describe the best-fit line.
D. Using the best-fit line described in part C, calculate an experimental value for the resistivity of the wire material.