Unit III: Magnetic Effects of Current and Magnetism

Concept of the magnetic field, Oersted’s experiment. Biot - Savart law and its application to current carrying circular loop.Ampere’s law and its applications to infinitely long straight wire, straight and toroidal solenoids. Force on a moving charge in uniform magnetic and electric fields. Cyclotron.Force on a current-carrying conductor in a uniform magnetic field. The force between two parallel current carrying conductors – definition of ampere. Torque experienced by a current loop in a magnetic field;moving coil galvanometer – its current sensitivity and conversion to ammeter and voltmeter.Current loop as a magnetic dipole and its magnetic dipole moment. The magnetic dipole moment of a revolving electron. Magnetic field intensity due to a magnetic dipole (bar magnet) along its axis and perpendicular to its axis. Torque on a magnetic dipole (bar magnet) in a uniform magnetic field; bar magnet as an equivalent solenoid, magnetic field lines; Earth’s magnetic field and magnetic elements.Para-, dia- and ferromagnetic substances, with examples. Electromagnets and factors affecting their strengths. Permanent magnets.