A tiny electric dipole of dipole moment p is placed at a distance r from an infinitely long wire , with it's p normal to the wire. If the linear charge density of the wire is λ , the electrostatic force acting on the dipole is ?
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1 Answers
1357A tiny electric dipole of dipole moment p is placed at a distance r from an infinitely long wire , with it's p normal to the wire. If the linear charge density of the wire is λ , the electrostatic force acting on the dipole is ?
let the length of dipole be x
|Fnet|=q(λ/2πε0r-λ/2πε0(r+x))
=λq/2πε0[1/r-1/(r+x)]=λq/2πε0[x/r(r+x)]
=λq/2πε0[x/r2]=λ(qx)/2πε0r2
=λp/2πε0r2
Alternately
E=λ/2πε0r
dE/dr=-λ/2πε0r2
dE=-λdr/2πε0r2
|F|=q|dE|=λ(qdr)/2πε0r2=λp/2πε0r2