Question

What is the potential difference between 10sinθcosφ/r^2 at A(1,30,20) and B(4,90,60)?

(a) 2.386

(b) 3.386

(c) 4.386

(d) 5.386

The question was asked during a job interview.

Origin of the question is Electric Potential in chapter Electrostatic Fields of Electromagnetic Theory

Answer 1

Correct answer is (c) 4.386

The explanation is: Potential at A, Va = 10sin30cos20/1^2 = 4.6985 and Potential at B, Vb = 10sin90cos60/4^2 = 0.3125. Potential difference between A and B is, Vab = 4.6985 – 0.3125 = 4.386 volts.