In a closed conducting loop carrying a steady current
PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity
Problem
In a closed conducting loop carrying a steady current, the algebraic sum of potential differences across all elements is observed to be zero. Which of the following best explains this result?
(a) Because no charge is created or destroyed in the loop, conservation of charge forces the algebraic sum of potential differences to be zero.
(b) A charge that returns to its starting point has no net change in energy, so energy conservation requires the potential changes to sum to zero.
(c) In a steady-state circuit the electric field averages to zero around a closed path, so the line integral of E⋅dℓ—and therefore the total potential change—must vanish.
(d) Ohm’s law guarantees that the resistive drops exactly equal the battery emf, so regardless of how many elements are present the algebraic sum of voltages must be zero.