Elmira moves the magnets away from each other without changing their orientations, the magnetic potential energy between them decreases. Therefore, the correct answer is:
B) Decreases.
The magnetic potential energy between two magnets depends on their relative positions and orientations. In this scenario, Elmira is holding two magnets with their north poles touching, and they are repelling each other. When she moves the magnets away from each other without changing their orientations (keeping the north poles of both magnets facing each other), the magnetic potential energy between them changes.
Here's a step-by-step explanation of how the magnetic potential energy changes:
1. Initial Configuration: At the beginning, the two magnets have their north poles touching. In this configuration, there is a maximum magnetic potential energy because like magnetic poles (north-north or south-south) repel each other.
2. Separation: As Elmira moves the magnets away from each other while keeping their orientations the same (north poles facing each other), the distance between the magnets increases. When you move like magnetic poles farther apart, the magnetic potential energy decreases because the force of repulsion between them weakens with distance.
3. Final Configuration: When the magnets are sufficiently separated, the magnetic potential energy reaches its minimum value. This is because the force of repulsion between the magnets is at its weakest, and they are no longer in close proximity to each other.