Describe how turning off the electric current in an industrial electromagnet affects magnetic fields

Electromagnets are used in a number of everyday devices.

One useful characteristic of an electromagnet is the fact that you can vary its magnetic force by changing the amount and direction of the current going through the coils or windings around it. Loudspeakers and tape recorders are devices that apply this effect. Some electromagnets can be very strong and its power can be readily turned off and on. Junk yard electromagnets, common doorbells and electromagnetic locks are examples. Electromagnets can also be used to create continual motion when opposed by other electromagnets or permanent magnets. Examples include electric motors and maglev trains.