When an electric current flows through a wire, a magnetic field is generated around the wire. This interaction between magnetic fields and electric currents is a fundamental concept in electromagnetism.

One important principle that relates magnetic fields and electric currents is Ampere's law. Ampere's law states that the magnetic field along a closed loop is directly proportional to the current passing through the loop. This law allows us to calculate the magnetic field around a current-carrying wire or a loop of wire.

Another application of magnetic fields and electric currents is solenoids. A solenoid is a coil of wire that generates a magnetic field when an electric current flows through it. Solenoids are used in many devices, such as doorbells and electromagnetic locks, where the magnetic field produced by the solenoid can be used to perform a mechanical operation.

Furthermore, the concept of electromagnets is based on the relationship between magnetic fields and electric currents. An electromagnet is a coil of wire with an iron core that becomes magnetic when an electric current passes through it. Electromagnets are widely used in various applications, ranging from electric motors and generators to magnetic separation devices.