Why does a hydroquinone has a non zero dipole moment?

[Murtuza Tipu]

Why does hydroquinone possesses non zero dipole moment? The OH groups present at para positions on the benzene ring should cancel the effect of each other...if there is a plane change then exactly in which cases molecules do change planes?

 

[Bystander]

How far are the two dipoles from one another? Do the dipoles act through the same center?