Задача 30709.

When a source of EMF is short-circuited with an iron wire 50 cm long and a cross-section of 0.2 mm^2, a current of 3 A flows through the wire. When a source is short-circuited with a nickelin wire of the same size, a current of 1.25 A flows. Determine the EMF of the source.

Detailed solution with a brief record of the conditions, formulas and laws used in the solution, derivation of the calculation formula and answer.
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