Correct Answer - a
(a) `F_1=mg`
When bar is just ready to levitate,
`IlB=mg, I=(mg)/(lB)=((0.75kg)(9.80m//s^2))/((0.500m)(0.450T))=32.67T`
`epsilon=IR=(32.67A)(25.0Omega)=817V`
(b) `R=2.0Omega, I=epsilon/R=(817V)(2.0Omega)=408.5A`
`F_1=IlB=92N`
`a=(F_1-mg)//a=113ms^-2`