Electromagnetic Induction: Faraday's Law and Lenz's Law, Study notes of Physics

Download Electromagnetic Induction: Faraday's Law and Lenz's Law and more Study notes Physics in PDF only on Docsity! PHY2049: Chapter 30 1 Chapter 30: Electromagnetic Induction PHY2049: Chapter 30 2 Subjects Induced emf Faraday’s law (law #3 of electricity and magnetism) Lenz’s law Motional emf Magnetic energy Inductance RL circuits Generators, transformers PHY2049: Chapter 30 5 Faraday’s Law (Law #3 of E&M) dt ΦdN Bε −= emf Use Faraday’s law to calculate only the magnitude Use Lenz’s law to find the direction # of turns of the loop Flux through the loop PHY2049: Chapter 30 6 About the negative sign in Faraday’s law Lenz’s law: Direction of induced emf is such that resulting current opposes change in ФB. Let’s examine three ways to change ФB through a coil Change B Change area of the coil (motional emf) Change angle θ of the coil with respect to B (motional emf) Lenz’s Law PHY2049: Chapter 30 7 Q1 Is the induced emf and current clockwise or counterclockwise? Q2 What does the ammeter read, when the magnet is held in place? Clockwise Zero Q3 What happens while the magnet is being pulled back? Counterclockwise emf and current Q4 What happens if the S pole of the magnet is pushed toward the loop? Counterclockwise emf and current Check Point: Changing B