Magnetic Fields 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.
Circular motion in a magnetic field
Force between parallel wires
Ampère's law
Why magnetic force does no work
Field of a finite wire segment
Mass spectrometer
Hall effect
Torque on a current loop
Magnetic dipole
Magnetic force on a charge
Field of a toroid
Force on a current-carrying wire
Short answer 1. Define or explain: Ampère's law vs Biot-Savart
3 ptsShort answer 2. Define or explain: Velocity selector
3 ptsShort answer 3. Define or explain: Field of a long straight wire
3 ptsShort answer 4. Define or explain: Field at the center of a circular loop
3 ptsFree response
8 ptsTwo long, straight, parallel wires are separated by a distance d. The left wire carries current I and the right wire carries current 2I, both in the same direction.
A. Indicate whether the magnitude of the magnetic force exerted on the left wire by the right wire is greater than, less than, or equal to the magnitude of the force exerted on the right wire by the left wire, and state whether the wires attract or repel. Justify your answer using qualitative reasoning beyond referencing equations.
B. Derive an expression for the magnitude of the force per unit length exerted on either wire, in terms of I, d and physical constants.
C. Justify how your derived expression in part B is or is not consistent with your comparison in part A, and determine where between the wires the net magnetic field is zero.