Uniform Electric Field in Parallel Plates

Steps:

• Parallel plates with equal opposite charges create a uniform electric field E between them, directed from positive to negative plate.
• Force on a charge q is F = qE; since E is constant in magnitude and direction, F remains constant.
• Positive particle moves from positive plate X toward negative plate Y, along the field direction.
• No variation in field strength occurs between plates, so force magnitude stays the same.

Why C is correct:

• In a uniform electric field, the force on a charged particle is constant, as defined by F = qE where E is uniform.

Why the others are wrong:

• A: Force isn't due to distance from one plate alone; it's the net uniform field.
• B: Attraction to negative plate doesn't change force magnitude in uniform field.
• D: Moving with the field doesn't increase force; magnitude remains constant.

Final answer: C