Which of the following statements about the properties of the electric field produced by charged parallel plates is not correct?

Analyze the question: We need the statement that is NOT correct about the field between charged parallel plates.

Concept: For two large parallel plates carrying equal and opposite charges:

• Field between the plates: E = σ/ε₀ = Q/(ε₀A), which is uniform in the central region.
• Field outside the plates: approximately zero, because the fields of the two plates cancel.
• Near the edges, the field lines bulge outwards (fringing or edge effect), so the field is not uniform there.

Checking each option:

• A. Correct. Outside the plates the fields cancel, so E ≈ 0 apart from edge effects.
• B. Correct. Since E = Q/(ε₀A), the field depends on the charge on each plate (away from the edges).
• C. Correct. E = Q/(ε₀A), so E ∝ Q when the plate area is fixed.
• D. Not correct. It says the field is uniform everywhere between the plates. Near the edges the field lines curve outwards (fringing), so the field is not uniform there. Options A and B both carry the "except near the edges" qualification, but D does not, which makes D false as written.

Answer: D

Exam tip: In "which is NOT correct" questions, look for absolute words like "everywhere," "always," or "never." The examiner often hides the false statement behind one of them. For parallel plates, remember that the field is uniform only in the central region, not at the edges.