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## Main Question or Discussion Point

An infinite string with linear charge density [tex]\lambda[/tex] is put parallel to the axis of an infinite conducting grounded cylinder (V=0) of radius [tex]R[/tex], the distance between the string and the center of the cylinder is [tex]l[/tex]. Find the potential outside the cylinder.

Is it possible to solve this problem using the method of images, i.e. placing an image string with some charge density [tex]\lambda_{1}[/tex] inside the cylinder so that the cylinder will be an equipotential surface? If V weren't 0, I could place a string of equal charge (i.e. [tex]-\lambda[/tex]) somwehere inside and it should work, but for V=0, the charges can't be equal.

Is it possible to solve this problem using the method of images, i.e. placing an image string with some charge density [tex]\lambda_{1}[/tex] inside the cylinder so that the cylinder will be an equipotential surface? If V weren't 0, I could place a string of equal charge (i.e. [tex]-\lambda[/tex]) somwehere inside and it should work, but for V=0, the charges can't be equal.