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The magnetic field (marked B, indicated by red field lines) around wire carrying an electric current (marked I) Compass and wire apparatus showing Ørsted's experiment (video [1]) In electromagnetism , Ørsted's law , also spelled Oersted's law , is the physical law stating that an electric current induces a magnetic field .
The magnetic field lines of a current-carrying loop of wire pass through the center of the loop, concentrating the field there The magnetic field generated by passing a current through a coil. An electric current flowing in a wire creates a magnetic field around the wire, due to Ampere's law (see drawing of wire with magnetic field).
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other.Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, magnetism is one of two aspects of electromagnetism.
When the electric current in a loop of wire changes, the changing current creates a changing magnetic field. A second wire in reach of this magnetic field will experience this change in magnetic field as a change in its coupled magnetic flux, . Therefore, an electromotive force is set up in the second loop called the induced emf or transformer emf.
A current is induced in a loop of wire when it is moved toward or away from a magnetic field, or a magnet is moved towards or away from it; the direction of current depends on that of the movement. [9] In April 1820, Hans Christian Ørsted observed that an electrical current in a wire caused a nearby compass needle to move. At the time of ...
A current-carrying coil of wire induces a magnetic field according to Ampère's circuital law. The greater the current I , the greater the energy stored in the magnetic field and the lower the inductance which is defined L = Φ B / I {\textstyle L=\Phi _{B}/I} where Φ B {\textstyle \Phi _{B}} is the magnetic flux produced by the coil of wire.
The interaction is mediated by the magnetic field each current produces and forms the basis for the international definition of the ampere. [53] The electric motor exploits an important effect of electromagnetism: a current through a magnetic field experiences a force at right angles to both the field and current.
The induced magnetic field inside any loop of wire always acts to keep the magnetic flux in the loop constant. The direction of an induced current can be determined using the right-hand rule to show which direction of current flow would create a magnetic field that would oppose the direction of changing flux through the loop. [8]