Item RG101002: Energy is transferred when a magnet exerts a force on an iron object and the position of the object changes.
A student would like to investigate the energy transfer between a magnet and a piece of magnetic metal. He places a block of iron on a table and positions a barrier in front of the block of iron. Next, he moves a magnet close to the block of iron on the table, as shown in Figure 1. He raises the barrier, and the iron block moves toward the magnet (Figure 2). The iron block then sticks to the magnet and comes to a rest (Figure 3).
In which figure is energy being transferred by the magnetic force to the iron block?
- Energy is transferred in all of the figures because energy is transferred by a magnetic force whenever an iron object is close to a magnet.
- Energy is transferred in Figures 2 and 3 because energy is transferred whenever a magnet exerts a force on an iron object.
- Energy is transferred in Figure 2 because energy is transferred when a magnet exerts a force on an iron object and the position of the object changes.
- Energy is not transferred in any of the figures because magnets can only transfer energy to other magnets.
- Distribution of Responses
- Scale Score for Item Difficulty
(200[Easy]-800[Difficult]) - 527
- Students Responding Correctly
Group | Correct | Total | Percent |
---|---|---|---|
Overall | 812 | 2828 | 29% |
Grades | |||
4–5 | N/A | N/A | N/A |
6–8 | 423 | 1418 | 30% |
9–12 | 389 | 1410 | 28% |
Gender | |||
Male | 358 | 1280 | 28% |
Female | 426 | 1477 | 29% |
Primary Language | |||
English | 727 | 2546 | 29% |
Other | 61 | 203 | 30% |
- Disciplinary Core Ideas
- PS3.C When two objects interacting through a field change relative position, the energy stored in the field is changed.
- NRC Framework
- Magnets can exert forces on other magnets or on magnetizable materials, causing energy transfer between them (e.g., leading to changes in motion) even when the objects are not touching.