CLASS 6 January 31 Gauss law

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CLASS 6 (January 31) Gauss law Law of
conservation of charge. Maxwells equations in
integral form.
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Faradays and Amperes Laws in integral form
Faradays Law
The electromotive force around a closed path C
Is equal to the negative of the time rate of
the magnetic flux enclosed by that path.
Amperes Law
The magnetomotive force around a closed path C
is equal to the algebraic sum of the current due
to flow of charges and the displacement current
bounded by that path C.
Whirl or Eddy
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Gauss laws
For electric field
For magnetic field
There are origins and/or endpoints of D field
lines inside the volume surrounded by S.
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Maxwells equations in integral form
Faradays Law
Amperes Law
Gauss law for electrical field
Gauss law for magnetic field
In vacuum (Free space)
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Gausss Law for the magnetic field is not
independent of Faradays Law
Gausss Law for the electric field is not
independent of Amperes Law
(Conservation of charge)
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Maxwells equations for static fields
General form Always true!
True only for statics (False in general)
for all C
(No whirl (eddy) in static electric fields)
Conservation of charge
Coulombs Law
Lorentz force
Electric and Magnetic fields are INDEPENDENT!
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Application of
enable us to find the static electric field
for certain charge distributions IF THE
resulting E field possess SYMMETRY, to be able to
replace the integrals by expressions of E.
Electric field due to an infinitely long line
charge
Cylindrical symmetry Cylindrical coordinate system
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Electric field due to a spherical volume charge
uniform charge density In region
Spherical symmetry Spherical coordinates
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enable us to find the static magnetic field
Application of
for certain current distributions IF THE
resulting H field possess SYMMETRY, to be able to
replace the integrals by expressions of H.
Magnetic field due to a cylindrical wire of
current
Axis along z axis
Wire radius a
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