PHYS 102 Lecture Notes - Lecture 13: Provatas

• School: McGill University
• Department: Physics
• Course: PHYS 102
• Professor: Nick Provatas

Document Summary

Recap of the last lecture (review session) Again, take note that midterm will cover only up to 19. 2. This lecture does not cover midterm material. Va =vb potential difference across a and b. Constant whether going through r branch or r+r branches (they are in parallel) Each section has 1/(1/2r + 1/r) soequivalent resistance: 2 * [(2r*r)/(3r)] =4/3r. Used to solve more complex resistor network: junction/node rule. The sum of the currents entering a junction equals the sum of the currents leaving that junction. I + i2 = i1 for the first. I + i1 +i2 = 0 for the second. I = -(i1 +i2) for the second (rearranged) Note how it"s adding up the ones that are entering the junction and subtracting the ones that leave the junction. The algebraic sum of changes in potential around any closed path in the circuit is zero. The potential change increases for path traversing - terminal to + terminal of the battery.