Question 22N.1.SL.TZ0.19
| Date | November 2022 | Marks available | [Maximum mark: 1] | Reference code | 22N.1.SL.TZ0.19 |
| Level | SL | Paper | 1 | Time zone | TZ0 |
| Command term | Question number | 19 | Adapted from | N/A |
A loop of wire lies in a magnetic field directed into the plane of the page. The loop carries a current in a clockwise direction.
The magnetic force acting on the wire tends to
A. rotate the loop about the X axis.
B. rotate the loop about the Y axis.
C. reduce the radius of the loop.
D. increase the radius of the loop.
[1]
D
A relatively complicated application of the right-hand rule for the direction of the magnetic force on a current-carrying wire. The wire is not straight, and the rule should only be applied to a short section of the loop at one particular position, e.g. at the leftmost point of the loop. The force on this short section is directed outward from the center, and the symmetry argument shows that the same is true elsewhere around the loop. This question had a particularly large performance gap between HL and SL candidates.