Two long parallel wires are separated by a distance of 2 . 50   cm . The force per unit length that…

Two long parallel wires are separated by a distance of 2.50 cm. The force per unit length that each wire exerts on the other is 4×10-5 N m-1, and the wires repel each other. The current in one wire is 0.5 A. What is the current in the second wire? (Take μ0=4π×10-7 S.I. Unit)
  1. 12 A
  2. 8 A
  3. 6 A
  4. 10 A

Solution

The formula of force between two current-carrying wire placed parallel to each other in terms of current in each wire and separation between two wires is, 
F=μ02πr×i1i2×l, the value is given, 
Fl=4×10-5 N m-1

Fl=μ02πr×i1i2i2=Fl×μ02πr×i1i2=4×10-5×2.50×10-22×10-7×0.5=2×2.500.5=10 A

Asked in: MHT CET Full Test 9

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