A circular coil having N turns and radius r carries a current I. It is held in the XZ plane in a magnetic field Bî. The torque on the coil due to the magnetic field is
Bπr²IN
Br²IπN
Bπr²IN
Zero
Solution:
Correct option is A. Bπr²IN Magnetic moment of coil = NIÂj = NI(πr²)ĵ Torque on loop (coil) = M→ × B→ = NI(πr²)Bsin 90°(-k^) = NIπr²B(-k^).