explain why its D If released from rest, the current loop will Move upward. Move downward. Rotate clockwise. Rotate counterclockwise. Do something not listed here.
The correct answer and explanation is :
Correct Answer: D — Rotate counterclockwise
Explanation (300 words)
This scenario likely involves a current-carrying loop placed in a uniform magnetic field. For simplicity, imagine a vertical rectangular loop hanging in a uniform magnetic field directed into the page (denoted by “X” symbols). The loop is initially at rest and carries a steady current, say, clockwise when viewed from the front.
Each segment of the loop experiences a magnetic force given by the Lorentz force law:
[
\vec{F} = I \, \vec{L} \times \vec{B}
]
where:
- ( I ) is the current,
- ( \vec{L} ) is the direction of the current segment,
- ( \vec{B} ) is the magnetic field.
For the top and bottom horizontal segments, the magnetic forces are equal in magnitude and opposite in direction, so they cancel out. However, for the left and right vertical segments, the direction of current is opposite, so they experience forces in opposite vertical directions due to the cross product.
These opposing vertical forces on either side of the loop create a torque, causing the loop to rotate. Since the current flows downward on the left side and upward on the right, and the magnetic field is into the page, the left side feels a force up, and the right side feels a force down. This combination produces a counterclockwise torque.
Hence, the loop starts rotating counterclockwise when released from rest.
This behavior is the basis of electric motors, where torque is generated by interactions between current-carrying loops and magnetic fields.
So, the loop does not move up or down, and it does not rotate clockwise—it rotates counterclockwise due to the torque generated by the magnetic forces acting on the loop.
