08.+Magnetism+and+Electromagnetic+Induction

﻿ ﻿ __ ﻿ Magnetism  __  ** General Properties of Magnets/Magnetic Feilds with Permanent Magnets **  ** ﻿ ** All the magnets present in the universe are very attracting objects for any range of people. It properties of magnets attracts the child to the engineer. We can have the fun playing with magnets and we can also quantify their curious properties. Magnets attracts any type of iron objects and we all know that magnetic fields are invisible force fields. The magnetic lines of force cannot be visible to the human eyes but we can trace them and the lines can be seen as shown in the above figure. Iron filings are attracted by the magnets. We can also do the experiments with the magnets even at home. We need not have any laboratories for doing the experiments. **  ﻿ ﻿ ﻿ ﻿ ﻿ ﻿ **  **KEY TERMS** __ELECTROMAGNET__: A type of magnet in which an object is charged by an electrical current. Typically the object used is made of iron, which quickly loses magnetic force when current is reduced. Thus an electromagnet can be turned on or off, and its magnetic force altered, making it potentially much more powerful than a natural magnet. __ELECTROMAGNETISM__: The unified electrical and magnetic force field generated by the passage of an electric current through matter.

__ELECTRONS__: Negatively charged subatomic particles whose motion relative to one another creates magnetic force. __MAGNETIC FIELD__: Wherever a magnetic force acts on a moving charged particle, a magnetic field is said to exist. Magnetic fields are typically measured by a unit called a tesla.

__NATURAL MAGNET__: A chemical element in which the magnetic fields created by electrons' relative motion align uniformly to create a net magnetic dipole, or unity of direction. Such elements, among them iron, cobalt, and nickel, are also known as magnetic metals. __PERMANENT MAGNET__: A magnetic material in which groups of atoms, known as domains, are brought into alignment and in which magnetization cannot be changed merely by attempting to realign the domains. Permanent magnetization is reversible only at very high temperatures — for example, 1,418 ° F (770 ° C) in the case of iron. **﻿Key Concept**  ﻿   Most people are familiar with magnets primarily as toys, or as simple objects for keeping papers attached to a metal surface such as a refrigerator door. In fact the areas of application for magnetism are much broader, and range from security to health care to communication, transportation, and numerous other aspects of daily life. Closely related to electricity, magnetism results from specific forms of alignment on the part of electron charges in certain varieties of metal and alloy. ** How does it work/How the knowledge is used in our daily life﻿ ** “Newton's third law applies to pairs of bodies. If a body A exerts a force on a body B, then body B exerts an equal and opposite force on body A.” Magnetism, along with electricity, belongs to a larger phenomenon, electromagnetism, or the force generated by the passage of an electric current through matter. When two electric charges are at rest, it appears to the observer that the force between them is merely electric. If the charges are in motion, however—and in this instance motion or rest is understood in relation to the observer—then it appears as though a different sort of force, known as magnetism, exists between them. In fact, the difference between magnetism and electricity is purely artificial. Both are manifestations of a single fundamental force, with "magnetism" simply being an abstraction that people use for the changes in electromagnetic force created by the motion of electric charges. It is a distinction on the order of that between water and wetness; nonetheless, it is often useful and convenient to discuss the two phenomena as though they were separate.
 * Like magnetic poles repel; unlike magnetic poles attract
 * Magnetic fields exit from the north pole of a magnet and enter its south pole
 * Magnetic field lines always form closed loops.
 * A magnetic field exists around any carrying-current wire
 * A coil of wire carrying a current has a magnetic field. The field about the coil is like the field about a permanent magnet

Magnets are a part of our lives that we mostly take for granted. They are everywhere, and we use it for basic things that, in this 21st Century, we consider essential in our lives. What would our lives be without them? Is it possible to live without magnets? What influence do they have in our lives? Where do they come from anyway? In this project, we will explore magnets, where they are found, their nature, how to make magnets, how to find out their magnetic field, how to make a compass, how to build a simple electromagnet, how to build simple and parallel circuits, how to make toys, and last but not least, we will take scientific notes in the form of a journal to document our discoveries and pass it on to others who still do not know about magnets and their uses. We will observe scientifically, make predictions, conduct trials, construct graphs, all of these following instructions, and making our own as well.
 * "[|__Magnetism.__]**
 * " __Science of Everyday Things__. 2002. //Encyclopedia.com.// 28 Apr. 2011 < [|__http://www.encyclopedia.com__] >. **

Formulas
 * ** ﻿ ﻿  ** F=ILB: Force on a current-carrying wire in a magnet is equal to the product of the current, the length of the wire, and the magnetic field's strength (F-force, I-current, L-length, B-strength of the field)
 * F=qvB: Force of a magnetic field on a charged moving particle is equal to the charge of the particle, its velocity, and the field of strength (F-force, q-charge of the electron, B-strength of the field)

This right hand rule: used to determine the direction of forces when the current and magnetic fields are identified ** El e c t r o m a g n e t i c I n d u c t i o n  ** What is Electromagnetic Induction ? Electromagnetic Induction is the process of using magnetic fields to produce voltage, and in a complete circuit, a current. 

** Michael Faraday ** first discovered it, using some of the works of Hans Christian, His work started at first using different combinations of wires and magnetic strengths and currents, but it wasn’t until he tried __ moving __ the wires that he got any success. It turns out that electromagnetic induction is created by just that- __the moving of a conductive substance through a magnetic field.__

**Induced current , induced emf, Faraday's law of induction , Lenz's law, motional emf , induced electric field, and Maxwell’s equations . **



**1 Induction of a current in a coil of wire **

**Whenever there is a change in the number of magnetic field lines ****<span style="color: #002060; font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">passing through a loop of wire a voltage (or emf) is generated (or induced) in the loop of wire. ****<span style="color: #00b0f0; font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;"> This is how an electric generator works. The phenomenon is known as electromagnetic induction and is explained by Faraday's Law of Induction. **

**__ Electrical generator: __** A device for converting mechanical (kinetic) energy into electrical energy. **__ Galvanometer: __** An instrument used to measure the flow of electric current. **__ Potential difference: __** Also called voltage; the amount of electric energy stored in a mass of electric charges compared to the energy stored in some other mass of charges. **__ Transformer: __** A device that transfers electric energy from one circuit to another circuit with different characteristics. **__ Electric current: __** A flow of electrons.
 * __ Vocabulary ____ Key __ __ terms: __ **


 * <span style="color: #00b0f0; font-family: 'Calibri','sans-serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">Power and Intensity Ratios & the Unit of Measure **


 * Number of Decibels ||||  Power (W) and Intensity (I) Ratio  ||
 * ^  ||  +dB  ||  -dB  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.1 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.02  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.98  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.5 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.12  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.89  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.26  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.79  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">2 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.58  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.63  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">3 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">2.00  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.5  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">6 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">3.98  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.25  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">10 || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">10.00  || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.10  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">20 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">2   || <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.01  ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">30 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">3   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-3   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">40 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">4   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-4   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">50 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">5   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-5   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">60 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">6   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-6   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">70 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">7   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-7   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">80 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">8   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-8   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">90 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">9   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-9   ||
 * <span style="color: #000000; display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">100 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">10   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-10   ||
 * Voltage and Pressure Ratios & <span style="color: #002060; font-family: 'Cambria','serif'; font-size: 14pt; line-height: 115%;">the Unit of Measure **
 * **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">Number of decibels ** ||||  **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">Voltage and Pressure Ratio **  ||
 * ^  ||  **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">+dB **  ||  **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">-dB **  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.1 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.01  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.99  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.5 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.06  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.98  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.122  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.84  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">2 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.26  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.79  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">3 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">1.41  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.71  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">6 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">2.0  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.50  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">10 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">3.16  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.316  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">20 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">10.00  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.1  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">30 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">31.62  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.0316  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">40 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">2   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-2   ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">50 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">316.0  || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">0.00316  ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">60 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">3   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-3   ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">70 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">3162  ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">3.162 x 10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-3   ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">80 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">4   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-4   ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">90 || <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">31622  ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">3.162 x 10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-4   ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">100 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">5   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-5   ||
 * <span style="display: block; font-family: 'Arial','sans-serif'; font-size: 10pt; text-align: center;">100 ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">5   ||  <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">10 <span style="font-family: 'Arial','sans-serif'; font-size: 8pt;">-5   ||

<span style="display: block; line-height: normal; margin: 0in 0in 10pt; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; text-align: center;">**<span style="display: block; font-family: Calibri; font-size: 200%; line-height: normal; margin: 0in 0in 10pt; text-align: center;">__ Information about ____ Electromagnetic Induction __ ** <span style="background: none transparent scroll repeat 0% 0%; color: #0070c0; font-family: 'Arial','sans-serif'; font-size: 130%; line-height: 132%; margin: 0in 0in 7.5pt;">Many electrical devices operate on the principle of electromagnetic induction. Perhaps the most important of these is an electrical generator. An electrical generator is a device for converting kinetic energy (the energy of an object due to its motion) into electrical energy. In a generator, a wire coil is placed between the poles of a magnet and caused to spin at a high rate of speed. One way to make the coil spin is to attach it to a turbine powered by water, as in a dam. Steam from a boiler can also be used to make the coil spin.As the coil spins between the poles of the magnet, an electric current is generated. That current then can be sent out along transmission lines to homes, office buildings, factories, and other consumers of electric power. <span style="display: block; line-height: normal; margin: 0in 0in 10pt; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; mso-outline-level: 2; text-align: center;">** __<span style="color: #00b0f0; font-family: 'Calibri','sans-serif'; font-size: 18pt;">Example Worked Out ____<span style="color: #002060; font-family: 'Calibri','sans-serif'; font-size: 18pt;">Problems ____<span style="color: #00b0f0; font-family: 'Calibri','sans-serif'; font-size: 18pt;">From Both Topics __ ** ** 1) **** A straight wire carrying a 5.0-A current is in a uniform magnetic field oriented at right angles to the wire. When 0.10 m of the wire is in the field, the force on the wire is 0.20 N. what is the strength of the magnetic field, B? ** ** Given: Unknown: **  ** I=5.0A B=??? **  ** L=0.10m **  ** F=0.20N **

**__ F __**** =__ILB__ B=__F__ __0.20N__ B=0.40N/A•m ** ** B B IL (5.0A) (0.10m) or **** BOTH ARE EQUIVALENT ** ** B=0.40T ** ** 2) **** A beam of electrons travels at 3.0x10^6 m/s through a uniform magnetic field of 4.0x10^-2T at right angles to the field. How strong is the force acting on each electron? ** ** Given: Unknown: **  ** v=3.0x10^6 m/s F=??? **  ** B=4.0x10^-2T **  ** q=-1.60x10^-19C **

** F=qvB ** ** = (-1.60x10^-19C) (3.0x10^6 m/s) (4.0x10^-2T) ** ** =-1.9x10^-14N ** <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">3) Two point charges Q1= 5.0C Q2= 1.0nC are located at (-1, 1, -3) m and (3, 1, 0) m, respectively. Determine the electric field at Q1. <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">Q1= 5.0C is at (-1, 1, -3) m <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">Q2=1.0nC is at (3, 1, 0) m <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">Electric field, E at Q1 (-1, 1, -3) m is <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">E = (Q2/4 εr2) ar <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">r = (-1-3)ax + (1-1)ay + (-3-0)az <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">= -4ax -3az <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">r =¦r¦ = =5 <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">ar = (-4ax -3az) / 5 <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">E = [1.0* 10-9 * 9 *109 / 25] (-4ax -3az) / 5 <span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">E = -0.288ax -0.216az V/m <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">4) A circular coil of radius 2.0 cm is in a magnetic flux density of 10 wb/m2. If the plane of a coil is perpendicular to the field, determine the total flux around the coil. The flux density = 10 wb/m2 <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;"> Area of the coil, S = r2 <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">= *(2.0*10-2)2 <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">=4 *10-4 <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">Total flux = B.S Where B =Flux Density and S =surface area <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">As B and S are in same direction, <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">B.S = BS <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">= 10 * 4 *10-4 <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">= 12.56 mwb <span style="display: block; line-height: normal; margin: 0in 0in 10pt; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; text-align: center;">** __<span style="color: #002060; font-family: 'Calibri','sans-serif'; font-size: 24pt;">Quizzed <span style="color: #00b0f0; font-family: 'Calibri','sans-serif'; font-size: 24pt;"> Questions __ ** <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**1.** Magnetic materials are: <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**A)** only made of iron <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**B)** made from any metal <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**C)** iron, nickel and cobalt <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**2.** In a magnet, the domains: <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**A)** are aligned in the same direction <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**B)** are in different directions <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**C)** are not present <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**3.** The ends of a magnet are called: <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**A)** fields <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**B)** poles <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**C)** omains <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**4.** Unlike poles: <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**A)** attract <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**B)** have no effect on each other <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**C)** repel <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**5.** Like poles: <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**A)** repel <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**B)** have no effect on each other <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**C)** attract <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**6.** What will happen if the magnet is moved closer to, or frther away from, the loop? <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**A)** There will be an induced voltage in the loop that will increase when the magnet is moved closer and decrease when the magnet is moved farther away <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**B)** There will be an induced voltage in the loop that will decrease when the magnet is moved closer and increase when the magnet is moved father away <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**C)** There will be induced voltage in the loop that will not depend on how the magnet moves <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**D)** There will be no induced voltage in the loop <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">**7.** Why should the magnitude of the induced voltage change? ** ﻿C) ** Because, as the loop rotates, the magnitude of the magetic field through the loop changes   **8.**Why should the sign of the induced voltage change? **A)** Because, part of the timr there is an increasing flux and part of the time there is a decreasing flux  **B)** Because, as the loop rotates, the rate at which the flux through the loop changes varies   **C)** Because, as the loop rotates, the direction of the magnetic field changes   **9.** at will happen if the magnet is moved closer to, or father away from, the loop   **A)** There will be an induced voltage in the loop that will increase in magnitude when the magnet is moved closer and decrease in magnitude when the magnet is moved farher away   **B)** There will be an induced voltage in the loop that will decrease in magnitude when the magnet is moved closer and increase in magnitude when the magnet is moved farther away   **C)** There will be an induced voltage in the loop taht will not depend on how the magnet moves   **D)** There will be no induced voltage in the loop   **10.**What will happen if the size of the loop is increased or decreased? **A)** There will be and induced voltage in the loop that will increase in magnitude when the loop is increased and decrease, in magnitude when the loop is decreased  **B)** There will be an induced voltage in the loop that will decrease in magnitude when the loop is increased and increase in magnitude when the loop is decreased   **C)** There will be an induced voltage in the loop that will not depend on the size of the loop   **D)** There will be no induced voltage in the loop <span style="background: white; display: block; line-height: 132%; margin: 0in 0in 10pt; text-align: center;">**__<span style="color: #00b0f0; font-family: 'Times New Roman','serif'; font-size: 16pt; line-height: 132%;">Bibliography __** **<span style="color: black; font-family: 'Times New Roman','serif'; font-size: 16pt; line-height: 132%;">"Electromagnetic Induction." __UXL Encyclopedia of Science__. 2002. Retrieved April 12, 2011 from Encyclopedia.com: ****<span style="font-family: 'Times New Roman','serif'; font-size: 16pt; line-height: 132%;">[] ** **<span style="color: black; font-family: 'Times New Roman','serif'; font-size: 16pt; line-height: 115%;">"Generator." __The Columbia Encyclopedia, Sixth Edition__. 2008. //Encyclopedia.com.// (April 12, 2011). ****<span style="font-family: 'Times New Roman','serif'; font-size: 16pt; line-height: 115%;">[] **
 * <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">A) **<span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;"> Because, as the loop rotates, the magnitude of the flux through the loop changes
 * <span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">B) **<span style="color: #002060; font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%; margin: 0in 0in 10pt;">Because, as the loop rotates, the rate at which the flux through the loop changes varies
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 16pt; line-height: 115%;">"Magnetism." __Science of Everyday Things__. 2002. //Encyclopedia.com.// 28 Apr. 2011 <[|__http://www.encyclopedia.com__]>. **