Ideal source behavior: When a battery is connected to a purely series circuit, the current it delivers depends primarily on which single factor?

Difficulty: Easy

Correct Answer: total resistance

Explanation:


Introduction / Context:
Ohm’s law gives a direct relationship among voltage, current, and resistance in simple DC circuits. Recognizing what sets the current helps with power budgeting, fuse sizing, and verifying whether a design will overload a source.


Given Data / Assumptions:

  • Ideal battery providing a fixed DC voltage.
  • All elements are in series (single path for current).
  • No internal resistance or nonlinearities considered for the basic principle.


Concept / Approach:
For an ideal source of voltage V connected to a series resistance R_total, the current is I = V / R_total. Polarity sets direction, not magnitude. Terms such as “primary/secondary” relate to transformers, not DC sources. “Average resistance” is not an electrical parameter; only the algebraic sum matters in series.


Step-by-Step Solution:

Compute total resistance: R_total = R1 + R2 + ... + Rn.Apply Ohm’s law: I = V / R_total.Conclude that current depends solely on total resistance for a fixed V.


Verification / Alternative check:
Measure current while adding another series resistor; current decreases according to I_new = V / (R_total + ΔR), confirming dependence on total resistance.


Why Other Options Are Wrong:

  • Primary/secondary difference: Not applicable to simple battery circuits.
  • Polarity connections: Affect direction of current, not magnitude for given R_total.
  • Average resistance: Not an electrical standard; magnitude is set by the true total.


Common Pitfalls:
Ignoring internal battery resistance in real life; while small, it can limit current. The ideal model still teaches the governing dependency.


Final Answer:
total resistance

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