PHYSICS · Subjective · CBSE · Physics · Current Electricity · Current Electricity
Problem
With reference to direct-current networks, consider a circuit that contains several resistors and two sources of emf connected in opposition so that their positive terminals face each other in one of the loops.
(a) State Kirchhoff’s current law and Kirchhoff’s voltage law.
(b) Describe the sign conventions that must be followed for (i) potential drops across resistors and (ii) emfs of sources when algebraic sums of voltages are written for a closed loop.
(c) Explain why assigning an arbitrary direction to every branch current at the start of the analysis does not affect the final numerical answers.
(d) For a hypothetical circuit consisting of two loops P–Q–R–P and Q–S–R–Q that contains resistors R1, R2, R3 and two opposing sources E1 (in loop P–Q–R–P) and E2 (in loop Q–S–R–Q), write the algebraic equations for the two loops and for one junction using the conventions you have stated.