Three charges are arranged as shown below.

(a) Find the net electric field at point P (show the direction of E from each charge at point P and express the net electric field in unit vector notation).

(b) Find the electric potential of the three charges at point P.

(c) How much potential energy of the system of the three charges will change if a fourth charge of -2q moves from infinity to point P?

(d) What will be the net electric force vector (in unit vector notation) on the fourth charge of -2q?

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