Passage I

Some students conducted 4 studies using slidewire generators of various sizes. Each slidewire generator contained a U-shaped electrical conductor (USEC), a movable conducting rod of length L that connected the sides of the USEC, and an ammeter (A). All conductors were made of the same metal. Using a motor-driven shaft attached to the conducting rod, the students could move the rod either to the left or to the right at speed v (see Figure 1).

In each trial, the slidewire generator was placed perpendicular to a magnetic field of strength B that pointed vertically toward the ceiling. The field was constant in strength and direction. When the rod was moved, amount an of electrical current, I, was generated in the circuit made by the USEC and the conducting rod (see Figure 2).

I was positive when the current moved clockwise through the circuit and negative when the current moved counter-clockwise through the circuit.

Study 1

The students moved a rod of length L = 0.20 m to the right at various v and measured I in milliamps (mA) for each v (see Table 1). B was the same across the 3 trials.

Study 2

The students moved rods of various L to the right at v = 0.20m/sec and found I for each rod (see Table 2). For each trial, B = 0.40 tesla (T).

Study 3

The students moved a rod of L = 0.20 m to the right at v = 0.20m/sec in fields of various B and found I for each B (see Table 3).

Study 4

The students moved a rod of L = 0.20 m to the left at various v and found I for each v (see Table 4). In each trial, B was the same as in Study 1.