Question

Find the direction of electric field at point $P$ for the charge distribution as shown in figure.

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

Answer 1

The correct option is A Along positive $y$- axis

Direction of force due to negative charge will be from $P$ to mid point of $-$$Q$.

Direction of force due to positive charge will be from mid point of $Q$ to $P$.

Due to symmetry of both the charges with respect to point $P$, both the above forces will be equal in magnitude.

Hence when both the above force add together, the horizontal force components cancel each other and only the vertical force component is remained, which is along positive y-axis.