QJEEAdv21Ph526c: JEE Advanced 2021 Physics - Class 12 JEEAdv21Ph526c Solution: The work done in bringing the dipole from infinity to a…

Question

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The work done in bringing the dipole from infinity to a distance r from the center of the loop by the given process is proportional to

Accepted Answer

ϕ = L i = \frac{μ_{0} m}{2 π r^{3}} \times π a^{2}

\Rightarrow i = \frac{μ_{0} m π a^{2}}{2 π r^{3} L} \Rightarrow i \propto \frac{m}{r^{3}}

m^{'} = π a^{2} i = \frac{μ_{0} m π^{2} a^{4}}{2 π r^{3} L}

F = \frac{k m^{2} π^{2} a^{4}}{2 π r^{7} L}

W = \int F d r \propto \int \frac{m^{2} d r}{r^{7}} \Rightarrow W \propto \frac{m^{2}}{r^{6}}

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