Question

An electric motor is a device that transfers electrically stored energy into kinetic energy. A very crude one would consist of a conducting wire shaped as a loop with a steady electric current passing through it placed in a uniform magnetic field. Let's imagine that the magnetic field is directed along the positive xx-axis, which we'll set up as going from left to right. The yy-axis points up and the zz-axis points out. Assume an absence of any frictional effects.

Which combination of options below are the most accurate combination of statements? [Enter your answer as a string of the letter options you believe are correct. For instance, if you think options A, D, and E are correct, then enter "ADE"]

A) If the current loop's dipole moment is initially aligned with the field, then it will flip back until it is anti-aligned, and then forth.
B) Maximum potential energy in this system occurs when the dipole moment points in the −i^−i^ direction
C) If the dipole moment initially points along the k^k^ direction, it's left end will feel a force pushing in along the −k^−k^ direction.
D) If the dipole moment initially points along the k^k^ direction, it's right end will feel a force pushing out along the k^k^ direction.
E) None of the above

Answer 1

(E) None of the above.

because all the remaining statements are incorrect.

A) If the current loop's dipole moment is initially aligned with the field, then it will flip back until it is anti-aligned, and then forth. its false statement.
B) Maximum potential energy in this system occurs when the dipole moment points in the −i direction. Maximum potential energy in this system occurs when the dipole moment points in the +i direction.
C) If the dipole moment initially points along the k direction, it's left end will feel a force pushing in along the −k direction.

If the dipole moment initially points along the k direction, it's left end will feel a force pushing in along the +k direction.
D) If the dipole moment initially points along the k direction, it's right end will feel a force pushing out along the k direction.

If the dipole moment initially points along the k direction, it's left end will feel a force pushing in along the -k direction.