As the force between the two coils is attractive hence currents in the coil must be in the same direction and the force, F∝2πdI1I2 where I1 and I2 are the currents flowing through the coils.
JEE Main 2013 — Physics Electromagnetism
One of the two small circular coils, (none of them having any self - inductance) is suspended with a V-shaped copper wire, with plane horizontal. The other coil is placed just below the first one with plane horizontal. Both the coils are connected in series with a dc supply. The coils are found to attract each other with a force. Which one of the following statements is incorrect?
Held on 25 Apr 2013 · Verified 6 Jul 2026.
Both the coils carry currents in the same direction.
Coils will attract each other, even if the supply is an ac source.
Force is proportional to d−1
Force is proportional to d−2
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