Problem 2
A point charge q is in vacuum. Find field and potential at distance r, with potential zero at infinity; kₑ=1/(4πε₀). Use the stated ideal model: quantities are constant or vary only as specified, with no extra drag, losses, or external influences. State a sign convention, keep units consistent, and use a classical approximation only where appropriate. (a) Set up the governing equation from a fundamental law. (b) Solve for the requested quantity under the stated conditions. (c) Check the result using a suitable limit, sign, or unit test, and report both the expression and its physical meaning.
problems.proof.stepOf
problems.proof.analysis
The boxed expressions answer the parts in order. Signs, conditions of validity, and constants follow the conventions in the statement.