If Danica is in a mile run race with Emmalee. Emmalee runs the mile in 4 minutes. At what speed does Danica need to run to
beat Emmalee's mile run time.

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr

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.