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How to apply Gauss's Law
Jun 10, 2025
This video is about few observation that might prove helpful while solving Gauss's Law. Before watching this video you can also watch our two previous videos on Gauss's law. https://www.youtube.com/watch?v=T8bjzTsZyqE https://www.youtube.com/watch?v=KNERqAu3aWU
View Video Transcript
0:01
in this video we will learn how to apply
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ca's law caes law is valid for any
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distribution of charges and for any
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closed
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surface now we already know that if we
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know about distribution of charges in a
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system and if it has enough symmetry to
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let us evaluate the integral in gau's
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law we can easily find the electric
0:30
field again if we know the field we can
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use the gau's law to find the charge
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distribution we will now see how could
0:44
we solve problem using causes law I
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would mention the steps through few
0:50
observation that might prove useful
0:52
while solving causes law problem
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[Music]
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now now before solving any problem or
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applying gs's law you must know that
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gs's law is the most useful in situation
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where the charge distribution has a
1:11
spherical or cylindrical symmetry in
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such situations you can find the
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direction of electric field using the
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symmetry of distribution of
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charges so begin your problem analysis
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by finding the symmetry of charge
1:34
distribution now after symmetry you have
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to select the surface to use with gau's
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law and such a surface is called Gan
1:44
surface and I have already talked about
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Gan surface in the video where I
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introduced the concept of causes
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law usually you can evaluate the
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integral and GES law only if the goian
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surface and and charge distribution have
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some symmetry property so if charge
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distribution of your problem has
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cylindrical symmetry choose Gan surface
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to be a coxial cylinder and if your
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charge distribution has a spherical
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symmetry choose Gan surface to be a
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concentric
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sphere now that you had chosen the gion
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surface for your charge distribution you
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can carry out the integral in G's log
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which is e e do da = Q upon
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Epson where this Q is charge enclosed
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inside the Gan
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surface now you can imagine your closed
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Gan surface to be made up of number of
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portions the integral over entire
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surface would be equal to the sum of
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integral over each
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portion now if electric field is at
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right angles to the surface of area a at
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all points and has same magnitude at all
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points of the surface then we have this
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e in perpendicular direction is equals
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to a constant and this integral e
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perpendicular do da is equal to e a
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again if electric field is perpendicular
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and points along inwards Direction then
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this e perpendicular is equal to minus Z
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and integral e perpendicular D is = to -
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E
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A again if electric field is parallel to
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surface at all points then this integral
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would be equals to0 also if electric
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field is equal to 0 at all points of the
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surface then also this integral would be
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equals to
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zero so you should keep all these points
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in mind while solving causes LW problem
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after solving your problem you can now
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evaluate your answer which might be a
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function
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describing how the magnitude of electric
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field varies with
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position you can now examine this
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function and check if if it makes sense
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or not if it does not make sense then
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you can again go through the trouble
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of correctly applying the gaues law to
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your problems and for more information
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and notes visit our website physics
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catalyst.com
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