10. which results in an increase in power?
doing less work in more time
doing less work in less time
doing more work in more time
doing more work in less time

answer: doing more work in less time

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.