1. Electromagnetic fields are magnets sensing other metal or something else it can make sound or light it can change.
Electric motors are a good example of electromagnetic fields. You can turn electric motors on and off but you cant turn a magnet on and off.
Electric motors uses a armature with magnets around it to create a magnetic field. Then that magnetic field moves the wheels. All of this can be controlled because it can be turned on and off.

2. Electromagnetic Fields

77. Magnetic fields
Electric motors
metal M
Electromagnetic fields