# Is the electric potential at the mid point between two equally oppositely charged plates zero

Is the electric potential at the mid point between two equally oppositely charged plates zero.

granted between the plates there is uniform fields. and what would the resultant potential graph look like due to the two plates. That is between the two plates only.

Remember that you can set the potential to be $$0$$ at any one point (except divergent potential points, like on charges). So the answer to this is, it depends on your choice. If the system is (a priori) set up such that one plate has $$V$$ and the other one is at $$-V$$, then the potential on the surface right in the middle is $$0$$ for infinite plates.

The potential graph in the region between the plates would look a straight line sloping down from the position of the positive plate to the negative plate.

• Thank you so much for taking the time out and answering the question, I really appreciate it. Jan 5 at 15:35

what would the resultant potential graph look like due to the two plates.

Assuming the plates are equal in size, and are arranged symmetrically, and the plates are very large compared to the gap between them and we take a line not too near the edges of the plates, then the graph will be linear.

Is the electric potential at the mid point between two equally oppositely charged plates zero

Still assuming symmetry between the plates, and if the plates are the only two objects in the universe, and potential is defined to be zero "at infinity", then yes.

If the universe is more complex then possibly not. For example, there could be a third, charged, object nearby.

If the zero of potential is defined as other than "at infinity", then possibly not. For example, we could arbitrarily choose one of the plates to have a potential of zero.

• Excellent points! In the usual, say practical case, as in dealing with an arrangement on a lab bench the choice of one of the plates at zero is quite common. Jan 4 at 16:21
• Thank you so much ! answers my question perfectly and yes i am considering an ideal situation where the plates are isolated. to ask a further question, in such a case can i really use electric field strentgh = (p.d accross plates)/(seperation) to find the electric potential at a given point, cuz this equation is considering one of the plate is grounded. so if one plate has -6v and other 6v, this equation would actually give 6v to be the potential at the mid point however it is actually zero Jan 5 at 15:42
• @sciencetadiumofficial, if one plate is grounded, then its potential is 0, not -6 or +6 V. (The meaning of the term grounded is that its potential is forced to be 0 V). Then the other plate must be at either -12 or +12 V. And there is no point between the plates with a potential of 0. Jan 5 at 16:47