So we know electric field is directed away from a positive charge and is towards a negative charge. But in an electric dipole we define a quantity called electic dipole moment which is directed from negative to positive (arbitrarily fixed direction). But then later it is also told that the electic field in a dipole(along axial line) is also in the direction of dipole moment. But how can electric field be directed from negative to positive? Shouldn't it be the opposite that the direction is directed from positive to negative charge? I'm sorry if my question sounds naive. I'm currently in initial stages of learning.
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$\begingroup$ Effectively the dipole isn't negatively charged $\endgroup$– SK DashCommented Jan 19, 2020 at 7:27
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$\begingroup$ See which charge is closer to the point $\endgroup$– SK DashCommented Jan 19, 2020 at 7:27
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$\begingroup$ this may help hyperphysics.phy-astr.gsu.edu/hbase/electric/dipole.html $\endgroup$– anna vCommented Jan 19, 2020 at 7:39
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$\begingroup$ @GiorgioP this question only answers about dipole moment direction which as I mentioned in the description is arbitrarily taken therefore this really doesn't answer my prime question about why electric field is taken with respect to direction of dipole moment $\endgroup$– A ShafiCommented Jan 19, 2020 at 8:37
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1 Answer
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The term “moment” can be considered synonymous with the term “torque”, a twisting force that causes rotation. The greater the magnitude of the dipole moment the greater the torque imposed upon when it is at right angles with the electric field, and therefore the greater its tendency to align with the electric field. For this alignment to occur, the dipole moment vector is defined opposite to the direction of the electric field vector.
Hope this helps.
