Question

The charge $Q=\pi C$ is distributed on a thin semicircular ring of radius $R=2m$. There is a uniform electrostatic field $|\overrightarrow{E}|=2N/C$ directed horizontal. The semicircular ring can rotate freely about a fixed vertical axis $AB$. Initially the ring is in static equilibrium a shown in figure. If we want to rotate it about the fixed axis by $90^{\circ }$ then minimum work required on the ring is $xJ$. Find the value

Answer 1

Answer: 8.00