Q. Let $E_{a}$ be the electric field due to a dipole in its axial plane distant $l$ and let $E_{q}$ be the field in the equatorial plane distant $l'$, then the relation between $E_{a}$and $E_{q}$ will be
A) $E_{a} = 4E_{q}$
B) $E_{q} = 2E_{a}$
C) $E_{a} = 2E_{q}$
D) $E_{q} = 3E_{a}$
Explanation
(c) Intensity of electric field at a point on the axis of dipole is given by
[image:1_image410.emf]
$E_{a} = \frac{1}{4\pi\varepsilon_{0}}.\frac{2p}{r^{3}}\frac{N}{C}\ldots..(i)$
Where, p is dipole moment.
Intensity of electric field at a point on the
Equatorial line of dipole is given by
[image:1_image411.emf]
$E_{q} = \frac{1}{4\pi\varepsilon_{0}}.\frac{p}{r^{3}}\frac{N}{C}\ldots..(ii)$
Dividing Eq. (i) by Eq. (ii), we get
$\frac{E_{a}}{E_{q}} = \frac{2}{1}$
$\Longrightarrow E_{a} = 2E_{q}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.