Reviewer for Grade 10 Students, History of Electromagnetism, Lecture notes of Earth science

Download Reviewer for Grade 10 Students, History of Electromagnetism and more Lecture notes Earth science in PDF only on Docsity! Brief History of Electromagnetism ➢ 1770-90. Cavendish and Coulomb established foundations of electrostatics ➢ 1820. Oersted made connection between flowing charge and magnetism ➢ 1820. Ampere identified currents as the source of all magnetism ➢ 1831. Faraday developed the concept of electric field showing the motor effect and EMI ➢ 1864. Maxwell put it all together (mathematical description) Described light as a propagating wave of electric and magnetic fields. PREDICTED the existence of EM radiation: electric & magnetic fields traveling as waves at the speed of light. ➢ 1887. Hertz DEMONSTRATED the existence of EM radiation ➢ 1819. Hans Christian Oersted noticed that the needle of a magnetic compass deflected when he turned on and off the current from a battery – confirmed a direct relationship between electricity and magnetism electric current produced a magnetic field around a conductor. When he moved the compass around the conductor, he noticed that the compass needle deflected at every point tangent to the circle around the conductor. The current-carrying conductor produced a magnetic field in a form of concentric circles near the conductor. Magnetic field around a STRAIGHT CONDUCTORS Right-Hand Grip Rule – determine direction of magnetic field 1. hold the current- carrying conductor & point thumb to direction of the current (+  -) 2. direction of the fingers encircling conductor = direction of the magnetic field Concurrent Circles - magnetic field strength around a current-carrying conductor. Near conductor = closer to each other = stronger field lines Far from the conductor = far from each other = weaker field lines. dart notations - express flow of current A. current-in and B. current-out (perspective of board/paper in front of person) Magnetic field around a CIRCULAR WIRE right-hand rule - determine direction of the magnetic field at the center of the loop When the current flows around a circular loop, the magnetic field forms a circle. All these circles add together. This makes a strong magnetic field in the center of the circular loop. Magnetic field around a COIL (SOLENOID) Solenoid - long coil of wire made up of many loops. When current moves along the wire of the solenoid, the current produces a magnetic field.