The torque and magnetic potential energy of a magnetic dipole in most stable position ina uniform magnetic field `vec(B)` having magnetic moment `vec(

Monjur Alahi

The torque and magnetic potential energy of a magnetic dipole in most stable position ina uniform magnetic field `vec(B)` having magnetic moment `vec(m)` will be
A. `-mB,zero`
B. `mB,zero`
C. `zero,mB`
D. `zero,-mB`


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Salim Ahmed Kawsar

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Correct Answer - D
Torque, `"Torque", vec(tau)=vec(m)xxvec(B)=mB sin theta`
and magnetic potential energy `U_(m)=vec(m).vec(B)=mB sin theta`
`theta=0^(@)` the dipole will be in most stable position
`pi=mB sin theta=mB sin 0^(@)=0`
`and U_(m)=-mB cos theta=-mBcos 0^(@)=-mB`

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