Question

Four points charges, each having a charge q are placed on the four corners A, B, C and D of a regular pentagon $ABCDE$. The distance of each corner from the centre is a. Find the electric field at the centre of the pentagon.

Answer 1

$E_A=E_D⟶$ cancels out.

$\sqrt{E_B^2+E_C^2}=E_{net}$

$E_{net}=\sqrt{2}E$

$=\sqrt{2}\times \frac{1}{4\pi {ϵ}_0}\times \frac{q}{a^2}$