3. Consider the point charges in the following gure. Assume point P is a place of interest in the following gure, and distances from each point charge to point P is labeled as 1'}, r2, and r3. (a) Write the general expression to determine the electric potential at point P due to the three charges. (13) Given that r; = 0.5 cm, r2= 0.8 cm, r3= 1.6 cm, q1= q2 = qs= 1.6 X 10'\" C, determine the value of the electric potential at point P