What is the E-field between two plates of voltage V, separation D?

Question

I asked this a few days ago but didn't get any answers. This was (a small) part of my final, I've been wondering about it ever since. Two parallel plates were set up as to create a uniform electric field between them -- the potential difference across the plates was V, and they were separated by distance D. That is the only information given (not given charge or charge density or anything). What is the electric field?

I guessed just V/D, but I'm not sure if that makes sense, considering the SI unit of E-field should be coulombs per meter, not volts per meter. Any help is appreciated.

Answer 1

Basically, you are describing a capacitor with two plates separated some distance with a given surface area. The dielectric between the plates is air. The capacitance and; thus, the electrostatic field between the plates vary with surface area, dielectric, and distance between the plates.

See: Capacitance and Capacitors

http://www.techlearner.com/DCPages/DCCap...

Answer 2

The electric field is by definition the force per unit charge, so that multiplying the field times the plate separation gives the work per unit charge, which is by definition the change in voltage.

ED=FD/Q=W/Q=(Change in V) for a constant electric field

Units: (N/C) m =Nm/C=Joule/C = Volts

Answer 3

No, the unit of E is newton/coulomb, not coulomb/meter. And a newton/coulomb is the same as a volt/meter.