Question

Find the torque when a rectangular coil is placed in an uniform magnetic field and carrying current.​

Answer 1

torque is B I A

B is mag. field

I is current

A is area

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Answer 2

τ=NIABsinθ 

We know that when an electric dipole is placed in external electric field then torque experienced by the dipole is 

τ=P X E=PEsinθ

Where P is the electric dipole moment

comparing expression for torque experienced by electric dipole with the expression for torque on a current loop i.e ,

τ=(NIA)Bsinθ

if we take NIA as magnetic dipole moment (m) analogus to electric dipole moment (p),we have

m=NIA                  

then

τ=m X B                  

The coil thus behaves as a magnetic dipole