Question

Question 4: Two negative point charges of the same magnitude fixed at P and Q. A free positive charge is placed at the midpoint between P and Q. Discuss what happens to the positive charge at T when it is displaced slightly a) in a direction perpendicular to PQ b) towards P along the line PQ

Answer 1

Two negative charge at P & Q of same magnitude five positive charge at T. a) when positive change at T is displaced in direction perpendicular to PQ F_PT and F_QT are attractive force acting along TP and TQ respectively. therefore therefore five positive charge experiences resultant attractive force in opposite direction to the motion of free charge perpendicular to PQ. b.) when positive change at T moves towards P along PQ. Here free charge moves along PQ toward P only as net attractive force from P is greater than Q due to force inversely proportional to the distance square (F alpha 1/d^2)