Ten charges are placed on the circumference of a circle of radius R with constant angular separation between successive charges. Alternate charges 1,…

Ten charges are placed on the circumference of a circle of radius $\displaystyle R$ with constant angular separation between successive charges. Alternate charges $\displaystyle 1$, $\displaystyle 3$, $\displaystyle 5$, $\displaystyle 7$, $\displaystyle 9$ have charge (+q) each, while $\displaystyle 2$, $\displaystyle 4$, $\displaystyle 6$, $\displaystyle 8$, $\displaystyle 10$ have charge ( $\displaystyle -q$ ) each. The potential V and the electric field E at the centre of the circle are respectively : (Take $\displaystyle \mathrm{V}=0$ at infinity)