Physic Labs

Problem 2

An initially uncharged capacitor CC is connected in series with resistor RR and ideal emf E\mathcal E. Find q(t)q(t), i(t)i(t) and the time to reach half the final voltage. (a) State the assumptions and establish the governing equation for the requested quantity. (b) Solve it in terms of the given symbols, identifying the direction, sign, or physical nature of the result. (c) Check a simple limiting case and state when the model remains valid. Use SI units consistently, retain the symbols in the setup, and enforce all geometric constraints and initial conditions.
t1/2=RCln⁡2t_{1/2}=RC\ln2
problems.proof.analysis

Check the dimensions of the final expression and test a simple physical limit. This independent check can expose a sign error or a missing factor in the derivation.

problems.proof.pitfall. Do not discard an initial condition or stated constraint; an algebraic root outside the physical domain is not an answer.