lectric field produced by the infinite line charges at a distance \(d\) having linear harge density \(\lambda\) is given by the relation,
$$
\Rightarrow \lambda=2 \pi \varepsilon_{0} d E
$$
$$
E=\frac{\lambda}{2 \pi \varepsilon_{0} d}
$$
$$
\begin{aligned}
&\text { Where, } \mathrm{d}=2 \mathrm{~cm}=0.02 \mathrm{~m} \\
&\mathrm{E}=9 \times 10^{4} \mathrm{~N} / \mathrm{C} \\
&\text { o Permittivity of free space and } 1 / 4 \pi \varepsilon_{0}=9 \times 10^{9} \mathrm{Nm}^{2} \mathrm{C}^{-2}
\end{aligned}
$$
Therefore
$$
\lambda=\frac{0.02 \times 9 \times 10^{4}}{2 \times 9 \times 10^{9}}
$$
\(=10 \mu \mathrm{C} / \mathrm{m}\)
Therefore, the linear charge density is \(10 \mu \mathrm{C} / \mathrm{m}\).
