Finding the force a magnetic field exerts on a current-carrying wire, with a demonstration of a wire jumping in a strong magnetic field.

Finding the force on a moving charge in an electric and magnetic field. Finding the total force on a wire in a magnetic field.

Sample calculation of the force on a wire in a magnetic field from a demonstration earlier in the lecture.

Introduction to motor building contest. Discussion of force and torque on a current loop in a magnetic field, with example of current meters in cars.

Definition of a commutator, with further explanation of the motor contest.

Creating a motor from a current loop where the current is manually reversed after every 180° of rotation.

Magnetic force on a current-carrying wire, with diagrams. Forces felt by wires with parallel and anti-parallel currents, with links to visualizations.

Force and torque on a rectangular current loop in a uniform magnetic field. Magnetic dipole moment μ is defined, with links to visualizations of how torque tends to align μ with B. Force on a magnetic dipole in a non-uniform field, with diagrams. Links to visualizations showing the force on one dipole from another dipole.

Table of important values and equations for resistors, capacitors, and inductors. Brief review of what happens in RC, RL, LC, and RLC circuits.

Equations for fields created by a single moving charge or a current, as well as for the force on a current-carrying wire. Right hand rules for cross products, with diagrams.

Overview of project in which students build a motor using little more than magnets, paper clips, a block of wood, and copper wire.

Magnetism from empirical evidence; Lorentz force on charge and wires; Electron trajectories; applications to modern physics; work done by B-fields.

B-fields defined; force on moving charge, straight wire; F = 0 for current loop.

Torque on current loop; loop as magnetic dipole; dipole moment and force on dipole; spinning compass needles.

Using vector product; worked problems on rolling and suspended conducting rods, moving charges, and bar magnet.

Seven questions with answers and explanations. Covers straight, coiled, bent, and curved wires in magnetic fields.

Question with answer and explanation.

Three questions with answers and explanations.

Question about force on a current-carrying bar in a magnetic field, with answer and explanation.

5-part power problem; finding resistance, power, voltage conditions, and Lorentz force in power lines.

Solution (PDF)

Calculating magnetic field energy and self-inductance of a current-carrying wire.

Solution (PDF)

Explaining in words why parallel currents attract and antiparallel currents repel.

Solution (PDF)

Determining the cause of a CRT beam offset slightly to the right.

Solution (PDF)

Finding the torque on a current-carrying loop in a magnetic field.

Solution (PDF)

Finding field of one loop and force exerted on the other. Solution not included.

Finding field of one loop and force exerted on the other.

Solution (PDF)^#

Video animation showing a current-carrying wire moving into a uniform magnetic field, then being pushed back out because of the resulting force on the wire.

Video animation showing the magnetic field and behavior of a coil of wire suspended above a magnet, when the current through the wire is flowing in one direction and then the other.

Interactive applet showing the magnetic field and behavior of a coil of wire suspended above a magnet, when the magnitude and direction of the current through the coil can be changed in real time.