A 12 V battery with negligible internal resistance powers a circuit in which the current splits at node M into two branches.
• Branch 1 contains a single 24 Ω resistor.
• Branch 2 contains two resistors, 36 Ω and 12 Ω, connected in series.
A student plans to insert three ideal ammeters: one in the main line before node M, one in Branch 1, and one in Branch 2.
Respond fully to the following prompts.
(a) Calculate the expected current in Branch 1, the expected current in Branch 2, and the expected main current before node M.
(b) Identify which of the three ammeter positions is least likely to alter the current it is intended to measure if the meters have small but non-zero internal resistance. Justify your choice qualitatively.
(c) After performing the experiment, the student measures a main current of 0.80 A, whereas the prediction from part (a) was 0.75 A. Propose two distinct, physically reasonable explanations for this discrepancy.