Question

Electric potential due to a point charge q at a distance r from the point is _______ (in the air).

(a) \(\frac {q}{r}\)

(b) q*r

(c) \(\frac {q}{r^2}\)

(d) \(\frac {-q}{r}\)

I had been asked this question in exam.

Enquiry is from Electrostatic Potential due to a Point Charge topic in chapter Electrostatic Potential and Capacitance of Physics – Class 12

Answer 1

Correct answer is (a) \(\frac {q}{r}\)

Easy explanation: Force on a unit point charge kept at a distance r from the charge=\(\frac {q}{r^2}\). Therefore, work done to bring that point charge through a small distance dr=\(\frac {q}{r^2}\)*(-dr). Therefore, the potential of that point is =\(\int_\alpha^r\frac {-q}{r^2}dr = \frac{q}{r}\).