Question

Find the direction of electric field at point $P$ due to the charge $-Q$ and $+Q$ distributed uniformly along the quarter as shown in figure.

• A. Along $+x$ - axis
• B. Along $-x$ - axis
• C. Along $+y$ - axis
• D. Along $-y$ - axis

Answer 1

The correct option is C Along $+y$ - axis


For every small element in upper quarter $(-Q)$ there is a small element in lower quarter $(+Q)$ whose electric field along $x$ - axis, cancels each other, but electric field along $+y$ - axis get added.
Therefore, net electric field is directed along $+y$ - axis.