Physics C: E&M · Unit 6 · Paper 1

Electromagnetic Induction 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.

Paper 1 Paper 2 Paper 3

Each paper is built from this unit’s 21 terms and is the same for everyone, so a teacher can assign “Unit 6, Paper 1” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.

Suggested time 37 min 34 points0/17 attempted

Inductance

Why Lenz's law must hold

Lenz's law

Inductor behavior at t = 0 and t = ∞

Determining induced current direction

Induced electric field

Faraday's law

Maxwell's equations qualitatively

Applying Lenz's law

Magnetic flux

Displacement current

Force opposing motion

Short answer 1. Define or explain: Mutual inductance

3 pts

Short answer 2. Define or explain: Self-inductance and back EMF

3 pts

Short answer 3. Define or explain: Rotating loop generator

3 pts

Short answer 4. Define or explain: Motional emf

3 pts

Free response

10 pts

EXPERIMENTAL DESIGN AND ANALYSIS (Question 3, 10 points). In Experiment 1, students must determine the inductance L1 of an inductor using a linear graph. They have multiple charged capacitors of different known capacitances and a voltmeter that records potential difference as a function of time. In each trial the inductor is connected to a charged capacitor through an initially open switch (Figure 1), forming an LC circuit when closed. For C–D (Experiment 2): students determine the inductance L2 of a new inductor connected to a 12 V battery, a 10 Ω resistor, and an initially open switch (Figure 2). After the switch closes, the current I and its rate of change dI/dt are recorded. Table 1: dI/dt = 280, 230, 150, 100, 68 A/s at I = 0.40, 0.50, 0.75, 0.90, 1.00 A.

A(i). Indicate quantities the students could measure to determine L1 using a linear graph. A(ii). Briefly describe a method to reduce experimental uncertainty.

B(i). Indicate what to graph on each axis to create a linear graph usable to determine L1. B(ii). Briefly describe the relationship between L1 and a feature of that graph (an equation may be included).

C(i). Label the axes with measured or calculated quantities (with units) so the graph is linear and usable to determine L2. C(ii). Create the graph with numerical scales and plotted points. C(iii). Draw a best-fit line.

D. Using the best-fit line from part C(iii), calculate an experimental value for L2.