Problem 3
Two very wide parallel plates separated by are held at potential difference , producing a uniform field; neglect edge effects. Axis points from the positive to the negative plate. A test particle of signed charge and mass lies between them. (a) Find field magnitude and direction. (b) Find the electric force, including for . (c) Find field work and potential-energy change for displacement along . Keep the sign convention consistent and use appropriate SI units throughout. Each part builds on intermediate results from the preceding part; apply a physical relation only where the stated model assumptions hold. Finally compare the answers with the initial conditions, expected trends, and an independent check when available.
problems.proof.stepOf
problems.proof.analysis
Apply the governing law for the stated model, using the sign convention in the problem. This provides the starting equation for the later parts.
problems.proof.pitfall. A negative charge feels force opposite the field; its sign does not reverse the field set by the plates.