Question

What is the magnitude of a point charge which produces an electric field of $2N/C$ at a distance of $60cm$? $(1/4\pi {\epsilon }_0=9\times 10{}^{9}N{m}^2/C^2)$

• A. $8\times {10}^{-11}$ coulomb
• B. $2\times {10}^{-12}$ coulomb
• C. $3\times {10}^{-11}$ coulomb
• D. $6\times {10}^{-10}$ coulomb

Answer 1

The correct option is A $8\times {10}^{-11}$ coulomb

$E=2N{C}^{-1}$

$r=60cm=0.6m$

$E=\frac{1}{4\pi {\epsilon }_0}.\frac{q}{r^2}$

$q=E{r}^2\left(4\pi {\epsilon }_0\right)=2\times \left(\frac{1}{9\times {10}^9}\right)\left({0.6}^2\right)=8\times {10}^{-11}$