Question

1. Calculate the potential that exists between points A and B shown in the given figure if q1=+5*10^-6 C and q2= -4*10^6 C. 

Answer 1

$\varphi=\varphi_1-\varphi_2=\frac kr(|q_1|-|q_2|)=9\cdot 10^3~V=9~kV.$