NEET 2022, Physics Q44: Coulomb's Law And Electric Field

NEET2022Physics

Two point charges $- q$ and $+ q$ are placed at a distance of L, as shown in the figure.

The magnitude of electric field intensity at a distance R (R $>>$ L) varies as :

Solution

The two equal and opposite charges form an electric dipole with moment $p = q L$ .

At distances much larger than the separation, the field of a dipole is $E = \frac{k p}{R ^{3}} 1 + 3 cos^{2} θ$ .

The radial dependence is therefore $E \propto \frac{1}{R ^{3}}$ .

Concept behind this question

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