anderson video - ampere's law 2 of 5 review | constants first, launch the video ampere's law. after watching the video, answer the follow-up question below. select to launch video part a a solenoid has 15 turns per centimeter of its length. the solenoid is twisted into a circle so that it becomes shaped like a toroid. what is the magnetic field at the center of each turn of the toroid? the current is 57 ma.