Practice portal › Electric Charge and Properties › Electric Dipole
Asked in GSEB Board March 2020 · Dipole moment and dipole field
Idea: far from a dipole (r 2a) the fields of +q and -q nearly cancel; what survives depends on the separation 2a.
On the axis: E = (2kp)/(r³); on the equatorial line: E = (kp)/(r³), with p = q(2a).
In every direction the field is proportional to p/(r³).
A point charge's field goes as 1/(r²); the dipole's falls off faster because its net charge is zero.
So the dipole's field falls off as 1/(r³).
Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.
Practise this with a timer