Electric field direction between charged parallel plates

Steps:

• Identify the plate with higher potential (+800V) as positive and lower (-300V) as negative.
• Electric field points from higher to lower potential, per the definition of electric field direction.
• For parallel plates, the field is uniform and perpendicular, with straight lines from positive to negative plate.
• Diagrams show field lines; select the one with lines directed from +800V to -300V plate.

Why B is correct:

• B depicts uniform field lines pointing from the +800V plate to the -300V plate, aligning with the electric field definition that $\vec{E} = -\nabla V$, directing from high to low potential.

Why the others are wrong:

• A shows lines from -300V to +800V, reversing the field direction.
• C illustrates curved or non-uniform lines, ignoring the uniform field of parallel plates.
• D shows lines diverging or converging, misrepresenting the straight, parallel field.

Final answer: B