Field
due to an infinitely long straight uniformly charged wire
Consider an infinitely long thin straight wire
with uniform linear charge density λ. The direction of electric field at every
point must be radial (outward if λ > 0, inward if λ < 0).
Consider a pair of line elements P1 and
P2 of the wire, as shown. The electric fields produced by the two
elements of the pair when summed give a resultant electric field which is
radial (the components normal to the radial vector cancel).
To calculate the field,
imagine a cylindrical Gaussian surface, as shown in the Fig. Since the field is
everywhere radial, flux through the two ends of the cylindrical Gaussian
surface is zero.
At the cylindrical part of
the surface, E is normal to the surface at every point, and its magnitude is
constant, s ince it depends only on r.
The surface area of the
curved part is 2Πrl, where l is the length of
the cylinder.
Faboulous sir ji itne saral tarik se esa lgta h ABC padh rha hu es se acha kya ho skta h
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