A particle of mass m and positive charge q is released from point A. Its speed is found to be v when it passes through a point B. Which of the two points is at higher potential ? What is the potential difference between the points ?

Explanation

The point A is at higher potential than B as the particle has gained kinetic energy while moving from A to B. The kinetic energy acquired by the particle is equal to loss in potential energy i.e
`DeltaK=q(V_(A)-V_(B)) implies (1)/(2)mv^(2)=q(V_(A)-V_(B))implies V_(A)-V_(B)=(1)/(2)(mv^(2))/(q)`