Electric field force on charged particle

Steps:

• Uniform electric field E between plates is E = V/d.
• Force on particle F = qE = qV/d.
• Acceleration a = F/m = (qV/d)/m = qV/(m d).
• Expression matches qV/(m d).

Why D is correct:

• D gives a = qV/(m d), from Newton's second law F = ma with F = qE and E = V/d.

Why the others are wrong:

• A is m d/(q V) = 1/a, the inverse of acceleration.
• B includes undefined v (initial velocity is zero), yielding unrelated m v/(q d).
• C is q d/(m V) = q/(m E), which is a/E, not acceleration.

Final answer: D