Question

Three charges are placed at the corners of the triangle in FIGURE $Q23.15.$ The $++$charge has twice the quantity of charge of the two - charges; the net charge is zero. Is the triangle in equilibrium? If so, explain why. If not, draw the equilibrium orientation.

Short answer

The couple due to opposite forces separated by distance makes the triangle rotate counterclockwise.

Step-by-step solution

Given information 

Explanation 

The electric field is uniform between the plates, so the force on the two positive charges due to negative charges on the first plate will act. Similarly, the force on the two negative charges due to positive charges on the second plate will at. Thus, the direction of two forces and acts in opposite direction. This causes the couple and hence the triangle will rotate counterclockwise.