1.) Figure 20.6 is a graph of the magnitude B versus time for a magnetic field that passes through a fixed loop and is oriented perpendicular to the plane of the loop. Rank the magnitudes of the emf generated in the loop at the three instants indicated from largest to smallest.
Select one:
1. b, c, a
2. c, b, a
3. b, a, c
4. c, a, b
5. a, b, c
6. a, c, b
2.) A bar magnet is falling toward the center of a loop of wire, with the north pole oriented downward. Viewed from the same side of the loop as the magnet, as the north pole approaches the loop, what is the direction of the induced current?
Select one:
a. along the length of the magnet
b. zero
c. counterclockwise
d. clockwise
3.) Two circular loops are side by side and lie in the xy-plane. A switch is closed, starting a counterclockwise current in the left-hand loop, as viewed from a point on the positive z-axis passing through the center of the loop. Which of the following statements is true of the right-hand loop?
Select one:
a. An induced current moves clockwise.
b. The current remains zero.
c. An induced current moves counterclockwise.
4.) You intend to move a rectangular loop of wire into a region of uniform mag- netic field at a given speed so as to induce an emf in the loop. The plane of the loop must remain perpendicular to the magnetic field lines. In which orientation should you hold the loop while you move it into the region with the magnetic field to generate the largest emf?
Select one:
1. (a) with the long dimension of the loop parallel to the velocity vector
2. (b) with the short dimension of the loop parallel to the velocity vector
3. (c) either way because the emf is the same regardless of orientation