Practice portal › Electric Charge and Properties › Electric Dipole
Asked in RS Academy GUJCET booklet · Torque, energy and work done
Idea: a point charge Q produces a non-uniform field, ⃗E=(kQ)/(r²)̂r, whose size and direction change from point to point.
Force: +q feels q⃗E₁ and -q feels -q⃗E₂. The two ends are at different points, so ⃗E₁ eq⃗E₂ and the net force q(⃗E₁-⃗E₂) is never zero.
Torque: if the dipole points along the radial line through Q, both forces act along that same line and have no turning effect, so the torque is zero.
At any other orientation the two forces form a turning couple and the torque is not zero.
So the net force is never zero, while the torque may be zero.
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