Figure shows a part of an electric circuit. The wires AB, CD and EF are long and have identical resistances. The separation between the neighboring wires is 1.0 cm. The wires AE and BF have negligible resistance and the ammeter reads 30 A. Calculate the magnetic force per unit length of AB and CD.


Current will equally divide into three parts since wires AB, CD and EF have identical resistance, 10 A each.


So, the Magnetic force on wire AB due to wire CD is,


= = N/m


and Magnetic force on wire AB due to wire EF is,


= = N/m


Total force per unit length,


= + = =


Now, magnetic force on wire CD due to wire AB,


= = N/m


and magnetic force on wire CD due to wire EF is


= = N/m


= + = =


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