The more coils, the more strength. An electromagnet with twenty coils would give out most energy. Think of it like this. Every coil gives out a specific amount of energy. For example, if we are only using numbers, five. If each coil gave out five, which would give out the most energy? If we had 5 coils, we'd get 25. If we had 10 coils, we'd get 50. If we had 15 coils, we'd get 75. If we had 20 coils, we'd get 100. Obviously, 100 is greater than 25, 50, and 75.
