A thin half ring of radius 35 cm is uniformly charged with a total charge of Q coulomb. If the magnitude of the electric field at centre of the half…

A thin half ring of radius $\displaystyle 35$ cm is uniformly charged with a total charge of $\displaystyle Q$ coulomb. If the magnitude of the electric field at centre of the half ring is $\displaystyle 100 \mathrm{~V} / \mathrm{m}$, then the value of $\displaystyle Q$ is $\displaystyle \_\_\_\_$ nC . ( $\displaystyle \epsilon_0=8.85 \times 10^{-12} \mathrm{C}^2 / \mathrm{Nm}^2$ and $\displaystyle \pi=3.14$ )