In 1820, Oersted showed that a conductor carrying current produces a magnetic field around it. If a magnetic needle is placed below a conductor carrying current, it gets deflected. If we make reverse direction of current, deflection and the magnetic field produced are reversed. This is called the magnetic effect of current. Electric current flowing in a conductor is equivalent to charges (electrons) in motion. Charges at rest produce electrostatic interaction, whereas charges in motion produce magnetic interaction. The magnetic field produced by a current carrying conductor interacts with a magnetic interaction. The magnetic field produced by a current carrying conductor interacts with a magnetic needle placed closed to it which gets deflected. If such a conductor carrying current is placed in place of the magnetic needle, then the magnetic field produced by the two interact with each other. If in place of the magnetic needle, we consider an electron beam it is also deflected. We have learnt about he steady state problems in electrostatics and magnetostatics considering electric and magnetic phenomena independent of each other. A stationary charge produce an electrostatic field whereas a moving charge is associated with an electric and a magnetic fields, such fields Have space and time variation. This phenomenon is said to be electromagnetism.