Two short magnetic dipoles m1 and m2 each having magnetic moment of 1Am2 are placed at point O and P respectively. The distance between OP is 1 meter. The torque experienced by the magnetic dipole m2 due to the presence of m1 is ______ ×10−7Nm.
Answer: 1
Solution
The figure places m1 along the vertical through O while OP is horizontal, so P lies on the equatorial line of the first dipole. There
B=4πμ0r3m1=1310−7×1=1×10−7T
directed antiparallel to m1, that is vertically downward. The second dipole points along OP, perpendicular to this field, so
τ=m2Bsin90∘=1×1×10−7=1×10−7Nm
The torque on the second dipole is 1×10−7 N m.
JEE Main · 2021 · 26 Aug 2021 · Shift 1 · Integer answer
