Electromagnetic Induction

<div dir="ltr" style="text-align: left;" trbidi="on"><div align="center"><span lang="EN-US" style="font-size: 20pt;"><span style="color: red;">Faraday’s Law of Electromagnetic Induction</span><br /> <span style="font-size: large;"><br /> </span> </span> </div><div align="center"><span lang="EN-US" style="font-size: large;">The magnitude of any induced e.m.f. (e) is proportional to the rate of change of magnetic flux linking the coil or circuit. This can be expressed mathematically as: </span></div><div align="center"><span style="font-size: large;">In words</span><span lang="EN-US" style="font-size: large;">, this equation says that the induced e.m.f. is equal to the rate at which magnetic flux is cut by the circuit or coil. </span></div><div class="O" v:shape="_x0000_s1026"><style> .O {color:black; font-size:149%;} a:link {color:#996600 !important;} a:active {color:#3B812F !important;} a:visited {color:#AFBF39 !important;} </style><style media="print"> <!--.sld {left:0px !important; width:6.0in !important; height:4.5in !important; font-size:103% !important;} --> </style><span style="font-size: large;"><o:shapelayout style="color: blue;" v:ext="edit"></o:shapelayout><o:idmap data="1" style="color: blue;" v:ext="edit"></o:idmap><p:colorscheme colors="#ffffff,#000000,#5f5f5f,#006633,#cc9900,#3b812f,#996600,#afbf39" style="color: blue;"></p:colorscheme></span><br /> <div class="O" v:shape="_x0000_s1026"><div align="center" style="color: red; text-align: justify;"><nobr><br /> <span style="font-size: large;"><span style="color: red;"> Lenz’ Law</span></span><span lang="EN-US" style="color: red; font-size: large;"> </span></nobr></div><div style="text-align: justify;"><span lang="EN-US" style="font-size: large;"><br /> </span> <br /> <div align="center"><span lang="EN-US" style="font-size: large;">The direction of any induced e.m.f. will be so as to oppose the change that it is producing it. Hence the negative sign.</span><span lang="EN-US"><b><u> </u></b></span></div></div></div></div></div>

Electromagnetic Induction

Faraday’s Law of Electromagnetic Induction The magnitude of any induced e.m.f. (e) is proportional to the rate of change of magnetic flux linking the coil or circuit. This can be expressed mathemati…

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Magnetic Circuits

<div dir="ltr" style="text-align: left;" trbidi="on"><div style="color: blue;"><b><span style="font-size: large;">Ampere’s Circuital Law</span></b></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;">SI units</span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;">Inet : is the net Ampere Turns (AT) enclosed within N-turns conductor.</span></div><div style="color: red;"><span style="font-size: large;">is the mean length of closed path (m</span></div><div style="color: red;"><span style="font-size: large;">H : Field Intensity (AT/m). </span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: blue;"><b><span style="font-size: large;">Permeability</span></b></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;">FProperty that tell us how easily a magnetic</span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;">field can flow through a material</span></div><div style="color: red;"><span style="font-size: large;">.</span></div><div style="color: red;"><span style="font-size: large;"> It is usually expressed in terms of relative permeability mr</span></div><div style="color: red;"><span style="font-size: large;"><br /> </span></div><div style="color: red;"><span style="font-size: large;"> The permeability is also the proportionality constant between an applied field intensity (H) and the resulting Magnetic Flux Density (B) : B = mH Þ m = mo. mr & mo = 4p´10-7.</span></div></div>

Magnetic Circuits

Ampere’s Circuital Law SI units Inet : is the net Ampere Turns (AT) enclosed within N-turns conductor.is the mean length of closed path (mH : Field Intensity (AT/m). Permeability FProperty that tel…

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Where Does the Magnetic Energy Come From

<div dir="ltr" style="text-align: left;" trbidi="on"><div style="color: red;"><span style="font-size: large;">A straight wire of length l is moved at right angles (with a velocity v) across a magnetic field of strength B. The wire will have an induced current I flowing through it and will thus experience a motor force on it given by F = B × I × L</span></div><div style="color: red;"><span style="font-size: large;">Lenz’ Law states that the motor force will oppose the movement of the wire (i.e. the force will be in the opposite direction to the wire’s movement).</span></div><div style="color: red;"><span style="font-size: large;">The rate at which mechanical work is being done (i.e. power) against the motor force is given by P = F × v = B × I × L × v </span></div><div style="color: red;"><span style="font-size: large;">We have previously derived an expression for the e.m.f. induced across such a straight wire: F = B × L × v</span></div><div style="color: red;"><span style="font-size: large;">The electrical power generated in the wire is then the product of the e.m.f. and the induced current : P = B × I × L × v = E × I</span></div></div>

Where Does the Magnetic Energy Come From

A straight wire of length l is moved at right angles (with a velocity v) across a magnetic field of strength B. The wire will have an induced current I flowing through it and will thus experience a mo…

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