Question

The electric field at a distance of 2 m from an infinite line charge of charge density 4 nC/m is

Answer 1

The electric field of linear charge

$$E=\frac{\lambda}{2\pi\epsilon_0r}$$

$$E=\frac{4\times 10^{-9}}{2\times3.14\times8.85\times 10^{-12}\times 2}=36\:\rm N/C$$