Question

What is the electric field intensity at a point at distance $20cm$ on a line making an angle of ${45}^o$ with the axis of the dipole of moment $10C-m$?

• A. $1.77\times {10}^{13}$ $V/m$
• B. $0.177\times {10}^{13}$ $V/m$
• C. $17.7\times {10}^{13}$ $V/m$
• D. $177\times {10}^{13}$ $V/m$

Answer 1

The correct option is A $1.77\times {10}^{13}$ $V/m$

Electric field at a point at distance $=20cm=20\times {10}^{-2}m$

angle $={45}^0$

dipole of moment $=10C-m$

Given, length of the dipole $\left(2\right)=10cm=0.1m$

or,

charge on the dipole $\left(q\right)=?$

$E=\frac{1}{4\pi {ϵ}_0}\times \frac{2(q\times 2l)}{{(r^2-l^2)}^2}$

$=9\times {10}^9\times \frac{2\times 10}{{\left(0.1\right)}^2}=1.77\times {10}^{13}V/m$