Q4) An aluminum wire 7.5m long is connected in parallel with copper wire 6m long when a current of 5A is passed through the combination, it is found that the current in the aluminum wire is 3 A. the diameter of aluminum wire is 1 mm. Resistivity of copper is 0.017 μ-m and of aluminum is 0.028μ-m, the diameter of cooper wire is: (6 Marks)