Question

The potential at a point 0.1 m from an isolated point charge is +100volt.What will be the nature of point charge?

Answer 1

Electric potential at p due to point charge q

$V=\frac{Kq}{r}$

$⟹+100=\frac{9\times {10}^9\times q}{0.1}$

$q=\frac{100\times 0.1}{9\times {10}^9}=\frac{10}{9\times {{10}^9}^{}}=\frac{+10}{9}\times {10}^{-9}C$

Hence it is a positive charge.