Question

Two point dipoles of dipole moment $\overrightarrow{p_{1}}$ and $\overrightarrow{p_{2}}$ are at a distance $x$ from each other and $\overrightarrow{p_{1}} \left|\right| \overrightarrow{p_{2}}.$ The force between the dipoles is :

• A. $\frac{1}{4\pi\varepsilon_{0}} \frac{4p_{1}p_{2}}{x^{4}}$
• B. $\frac{1}{3\pi\varepsilon_{0}} \frac{8p_{1}p_{2}}{x^{3}}$
• C. $\frac{1}{4\pi\varepsilon_{0}} \frac{6p_{1}p_{2}}{x^{4}}$
• D. $\frac{1}{4\pi\varepsilon_{0}} \frac{8p_{1}p_{2}}{x^{4}}$

Answer 1

Answer: (B)

$\frac{1}{3\pi\varepsilon_{0}} \frac{8p_{1}p_{2}}{x^{3}}$

Answer 2

Force of interaction
$F = \frac{1}{4\pi\varepsilon_{0}}. \frac{3p_{1}p_{2}}{r^{4}}$