The drawing shows a positive point charge +q1, a second pointcharge q2 taht may be positive or negative, and a spot labeled P,all on the same straight line. The distance d between the twocharges is the same as the distance between q1 and the spot P. Withq2 present the magnitude of the net electric field at P is thetwice what it is when q1 is presenn alone. Give that q1 = +.50 uC determine q2 when it is a) positive, b) negative