Answer:
- Decrease the number of loops of wire
- Decrease the current by lowering the potential difference of the battery.
- Move the electromagnet away
Explanation:
There is not context to know how the electromagnet is built and what the the points A, B, and C represent. Nevertheless, you can conclude from the graph that the force of the electromagnet decreased linearly from the situation A to the situation B.
The strength of the force from an electromagnet depends on:
- Number of loops of wire around the ferromagnetic core
- Current, which in turn depends on the potential difference (voltage)
- Ferromagnetic properties of the core
- Distance between the electromagnet and the spot were you are calculating the force.
How those factors can be modified to decrease the magnetic force from point A to point B:
- Decrease the number of loops of wire (the less the number of loops the less the weaker the electromagnet)
- Decrease the current by lowering the potential difference of the battery.
- Move the electromagnet away, because the farther the less the force.
