An infinitly long wire is charged uniformly with charge density $\lambda$ and placed in air, the electric field at distance r from wire will be:

$\frac{1}{4 \pi \varepsilon_0} \frac{\lambda}{r}$ $\frac{1}{4 \pi \varepsilon_0} \frac{\lambda}{r^2}$ $\frac{\lambda}{2 \varepsilon_0}$ $\frac{\lambda}{2 \pi \varepsilon_0 r}$

$\frac{\lambda}{2 \pi \varepsilon_0 r}$

The correct answer is Option (4) → $\frac{\lambda}{2 \pi \varepsilon_0 r}$