Question

An infinitely long thin straight wire has uniform linear charge density of $1/3{\text{Cm}}^{-1}$. Then the magnitude of the electric field intensity at a point $18\text{cm}$ away is $x\times {10}^{11}{\text{NC}}^{-1}$. The value of $x$ is _____.

Answer 1

The field due to an infinite linear charge density is,

$E=\frac{2k\lambda }{r}$

$=\frac{2\times 9\times {10}^9\times 1/3}{18\times {10}^{-2}}$

$=0.33\times {10}^{11}{\text{NC}}^{-1}$

$\therefore x=0.33$