A circular coil ABCD carrying a current i is placed in a uniform magnetic field. If the magnetic force on segment AB is F⃗, the force on the remaining segment BCDA is:
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A circular coil ABCD carrying a current i is placed in a uniform magnetic field. If the magnetic force on segment AB is F⃗, the force on the remaining segment BCDA is:

G1 Physics · Accepted Answer

Step 1: For a closed current loop in a uniform magnetic field, net translational force is ∮I(dℓ⃗×B⃗)=I(∮dℓ⃗)×B⃗=0. Step 2: Split current loop into segment AB and the remaining path BCDA. Step 3: For equilibrium of forces F⃗_AB+F⃗_BCDA=0 ⇒ F⃗_BCDA=−F⃗_AB. Magnitude F, answer A. Final answer: (A) −F⃗.