Induced Voltage and Inductance: Faraday's Experiments and Laws, Assignments of Physics

Download Induced Voltage and Inductance: Faraday's Experiments and Laws and more Assignments Physics in PDF only on Docsity! 1 Chapter 20 Induced Voltage and Inductance Assignments for the week: Reading 20.1 – 20.8 Recitation problems: Ch. 20: CQ-1, 2, 6, 8, 10, 13; P-2, 4, 10, 12, 18, 23, 39, 47. Homework problems (Due: Monday 03/03/2008): Ch. 20: P-13, 28. 1. Induced emf and magnetic flux (a) Can magnetic field generate electricity? Faraday’s Experiment: => A changing magnetic field can produce an emf, called the induced emf. It was found out that an emf can also be induced by changing the area or the orientation of closed loop, so the emf is actually induced by a change in a quantity called the magnetic flux. Michael Faraday (1791 – 1867) 2 (b) What is magnetic flux? The magnetic flux through a loop of area A is defined as: A SI units of flux: T m² = Wb (Weber) Φ ≡ B┴A = B A cosθ. Question: How many different ways by which the magnetic flux can be changed? 20.2 t N Δ ΔΦ −=ε 2. Faraday’s Law of Induction (a) What determines the level of the induced emf? The induced emf: (b) What is the polarity of the induced emf? The magnetic field of the induced current opposes the change in the magnetic flux (Lenz’s Law) Faraday’s law of magnetic induction. N => number of loops in the circuit. Active figure 20.4