An aluminum busbar inside a small power-distribution unit is fabricated as a flat rectangular strip of constant cross-section. The strip has a length of 25 cm, a width of 1.5 cm, and a uniform thickness of 0.20 mm. At operating temperature, the resistivity of aluminum is 2.8×10−8Ω⋅m. Engineers consider replacing the strip with a round aluminum wire of the same length that offers the same electrical resistance.
(a) Calculate the electrical resistance of the original rectangular aluminum strip.
(b) Determine the diameter of a circular wire, made of the same aluminum and having the same length, that would have identical resistance to the strip.
(c) Give one practical reason, unrelated to mass or cost, why the flat strip might be preferred over the round wire in this power-distribution application, and explain your reasoning.