EFFECTS OF ELECTRIC CURRENT In this unit, the student is exposed to • Earth’s magnetic field and magnetic elements • Basic properties of magnets • Statement of Coulomb inverse square law of magnetism • Magnetic dipole • Magnetic field due to a dipole along axial line and equatorial line • Torque acting on a bar magnet in a uniform magnetic field • Potential energy of a bar magnet placed in a uniform magnetic field • Magnetic properties – permeability, susceptibility etc • Classification of magnetic materials – dia, para and ferro magnetic materials • Concept of Hysteresis • Magnetic effects of electric current – long straight conductor and circular coil • Right hand thumb rule and Maxwell’s right hand cork screw rule • Biot-Savart’s law – applications • Tangent law and Tangent Galvanometer • Current loop as a magnetic dipole • Magnetic dipole moment of revolving electron • Ampère’s circuital law – applications • Solenoid and toroid • Lorentz force – charged particle moving in an electromagnetic field • Cyclotron • Force on a current carrying conductor in a magnetic field • Force between two long parallel current carrying conductor • Torque on a current loop in a magnetic field • Moving Coil Galvanometer “The magnetic force is animate, or imitates a soul; in many respects it surpasses the human soul while it is united to an organic body” – William Gilbert Learning Objectives 12th - 12th - - - - - Unit Magnetism and magnetic effects of electric current . INTRODUCTION TO MAGNETISM Figure . : Magnetic levitation Magnets! No doubt, their behaviour will attract everyone.
The world enjoys their benefits, to lead a modern luxurious life. The study of magnets fascinated scientists around our globe for many centuries and even now, door for research on magnets is still open (Figure . ). Many birds and animals have magnetic sense in their eyes using Earth’s magnetic field for navigation.
Magnetic sensing in eyes - for Zebra finch bird, due to protein cryptochromes Cry4 present in retina; the bird uses Earth's magnetic field