An infinitely long positively charged wire has a linear charge density \(\lambda=3 \mathrm{nC} / \mathrm{m}\). Calculate the electrostatic potential at distances of

(a)  \(1.0 \mathrm{~m},\)

(b)  \(2.0 \mathrm{~m}\),

(c)  \(6 \mathrm{~m}\) from the wire, assuming zero potential \(4 \mathrm{~m}\) from the wire.