Force between two parallel current carrying wires is given as
f=2πdμ0I1I2l
F∝I1I2
When I1,I2 are in same direction the I1I2is+ve ⇒ attraction ⇒ -ve
When I1I2 are in opposite direction then
I1I2=−ve
∴ Force = repulsive = +ve

JEE Main 2015 — Physics Electromagnetism
Two long straight parallel wires, carrying (adjustable) currents I1 and I2 , are kept at a distance d apart. If the force F between the two wires is taken as 'positive' when the wires repel each other and 'negative' when the wires attract each other, the graph showing the dependence of F, on the product I1I2 , would be:
Held on 11 Apr 2015 · Verified 6 Jul 2026.




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