Investigators are researching the appearance of a strange movement of objects in what the local community considers a haunted house.
the owners of the house attribute the cause to poltergeists; others blame overly strong magnetic fields could be the cause.
as a scientific investigator of paranormal claims, you decide to investigate. you will start by focusing on magnetic fields.

using a coil made of 219 turns of single-strand copper wire, you use a motor to rotate the coil at a constant angular speed of 40.0 revolutions per second at various orientations and locations throughout the room. in one particularly signficant orientation, you notice a maximum induced voltage of 3.15 v appearing in the coil.

if the radius of the coils is 1.00 cm, how strong was the magnetic field that produced this emf?