can anyone explain waht is the dipole moment.
See: Dipole Moment
Note also that there is a magnetic dipole moment. Your question did not specify which one you are looking for.
It would be helpful if you also indicate to what extent have you tried to seek the answer yourself, and if after doing that, you have specific parts that you do not understand. With internet access, it is unusual for anyone to ask a question cold without having to do some research on his/her own.
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