For a short dipole (dipole length a<< r), the ratio between the magnitude of the electric field at a point at distance r along its axis and the magnitude of the electric field at a point at same distance r on its equatorial plane, is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 2:1
For a short dipole (a much smaller than r), the field on the axis is twice the field on the equatorial plane at the same distance.
\( \displaystyle E_{\mathrm{axial}} = \frac{1}{4\pi\varepsilon_0}\,\frac{2p}{r^{3}} \)
\( \displaystyle E_{\mathrm{equatorial}} = \frac{1}{4\pi\varepsilon_0}\,\frac{p}{r^{3}} \)
\( \displaystyle \frac{E_{\mathrm{axial}}}{E_{\mathrm{equatorial}}} = \frac{2}{1} \)