ch22_arom


 * CHAPTER 22 ~ INDUCTION AND ALTERNATING CURRENT!**

A: Area of the loop B: strength of the magnetic field (T) math \displaystyle \Delta{t} math : time (s) N: number of turns in the coil (turns) math \displaystyle \Delta{V_{rms}} math : root-mean-square potential difference math \displaystyle \Delta{V} math : potential difference (V) P: power (W)
 * KEY VARIABLES:**

math \displaystyle emf=-N\frac{\Delta(ABcos\theta)}{\Delta{t}} math math \displaystyle \Delta{V_{rms}}=\frac{\Delta V_{max}}{\sqrt{2}}=0.707{\Delta{V_{max}}} math math \displaystyle I_{rms}=\frac{I_{max}}{\sqrt{2}}=0.707{I_{max}} math math \displaystyle \Delta{V_2}=\frac{N_2}{N_1}\Delta{V_1} math : this can also be looked at as a proportion : math \displaystyle \frac{N_1}{N_2}=\frac{V_1}{V_2} math math \displaystyle P_1=P_2 math math \displaystyle \Delta{V_1}I_1=\Delta{V_2}I_2 math
 * KEY EQUATIONS:**

SECTION 22-1 SECTION 22-2 SECTION 22-3
 * KEY CONCEPTS:**
 * Moving a conductor in an electric field or changing the magnetic field around a conductor will induce an emf (electromotive force) in the conductor through electromagnetic induction.
 * The charges already present in the conductor will be caused to move in opposite directions by the motion of the conductor through the field, therefore a current can be induced without a battery or other source present.
 * When a loop/coil of wire is moved linearly through a magnetic field the orientation of the loop will affect the current induced.
 * If the plane of the loop is perpendicular to the magnetic field, the current is greatest.
 * If the plane of the loop is parallel to the magnetic field, the current is zero.
 * If more magnetic field lines are cut by the loop of wire, the emf increases.
 * Lenz's law states that the magnetic field of the induced current opposes the change in the applied magnetic field.
 * Generators use induction to convert mechanical energy to electrical energy.
 * A continuously changing emf is produced by a rotating coil of wire inside a uniform magnetic field.
 * When the loop is perpendicular to the magnetic field, every portion of the loop is moving parallel to the magnetic field so no current is induced.
 * When the loop is parallel to the magnetic field, the sides of the loop are crossing the largest number of magnetic field lines so the largest emf is produced.
 * Alternating current is when the emf varies from zero to the maximum twice every rotation of the coil and follows a sinusoidal path.
 * The maximum potential difference is only reached during a small part of each cycle.
 * The effective potential difference is the square root of the average of the square of the potential difference over time (root-mean-square potential difference).
 * Electrical meters usually read rms values for alternating current.
 * Motors use an arrangement similar to generators to convert electrical energy to mechanical energy (the opposite of what a generator does).
 * Mutual inductance involves the induction of a current in one circuit by means of changing current in another circuit (seen most often as a transformer).
 * Two coils of wire wound on the same iron core changes the potential difference of an alternating current source.
 * The power produced by the output of a transformer is the same as the power consumed by the transformer.

The organization and overall structure match the 2002 edition of __Holt Physics__ by Serway and Faughn and many of the expressions and the ideas come from there as well. Much of wording and ideas also come from __Honors Physics Review Notes 2008-2009__ by Strong.

Citations:

Faughn, Jerry S. and Raymond A. Serway. __Holt Physics.__ New York, Holt. 2002. Strong, Tom. Course notes. Honors Physics. Dept. of Science. Mt Lebanon High School. May and June 2009.