Given, Linear charge density, λ=8nC/m=8×10−9C/m The relation between surface charge density and linear charge density can be given as r2kλ​=ε0​σ​ .....(i) where, k= Coulomb's constant, λ= linear charge density, σ= surface charge density, ε0​= absolute electrical permittivity of free space and r= distance. Substituting the values in Eq. (i), we get σ=r2kλε0​​=32×9×109×8×10−9×8.85×10−12​=0.424×10−9Cm−2=0.424nCm−2