Physics - Electrostatics Question with Solution | TestHub

For a short electric dipole, the electric field on its axial line at a distance $r$ from the center is given by $E=\frac{2kp}{r^3}$. Given $p=4\times 10^{-9}$ C-m, $r=2$ cm $=0.02$ m, and $k=9\times 10^9$ N m${}^2$ /C${}^2$.$E=\frac{2\times (9\times 10^9)\times (4\times 10^{-9})}{(0.02{)}^3}=\frac{72}{8\times 10^{-6}}=9\times 10^6$ N/C. The magnitude of the electric field is $9\times 10^6$ N/C.