The EPA is trying to decide whether or not to ban a certain chemical that has been associated with acid rain. What would be the most helpful i n their decision-making process?

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.