Question

Three positive particles of charges 1 μC, 2 μC, 3 μC, and 4 μC, are located at the corners of a square of side 1 cm. Calculate the potential in the center of the square, taking V = 0 at a great distance.

Answer 1

φ=φ1+φ2+φ3+φ4= k{(q1/r)+ (q2/r)+ (q3/r)+ (q4/r)}
a=0.01 m, r=a√2/2=0.007 m
k=9•10^9 F/m
φ= (9•10^9•10^-6/0.007) •(1+2+3+4)=1.29•10^7 V