Two long, straight wires are fixed parallel to one another a distance do apart. The wires carry equal constant currents 1, in the same direction. The attractive magnetic force per unit length between them if f = F/L. What is the force per unit length between the wires if their separation is 2d, and each carries current 2I0? A. f/4
B. f/2
C. 3f/2
D.) 2f

Option D

Explanation:

From the question we are told that:

The attractive magnetic force per unit length as

Separation Distance

Generally the equation for  Magnetic force between two current carrying wire is mathematically given by

Where

And

Then

Therefore s the force per unit length between the wires if their separation is 2d

Option D

where is the circuit diagram ?