Question

A uniform magnetic field of `3000G` is established along the positive z-direction. A rectangular loop of sides `10cm` and `5cm` carries a current `12A`. What is the torque on the loop in the different cases shown in the figure. What is the force on each case? Which case corresponds to stable equilibrium?

Answer 1

a) Torque `=300, G = 3000 xx10^(-4) T`
Area `A=10 xx5=50cm^(2)=(50)/(100xx100)m^(2)`
`tau= BIA =(3)/(10)xx12xx(50)/(100xx100)=18xx10^(-2)` Nm along Y-axis
b) Same as in (a)
c) `1.8xx10^(-2)` Nm along x-direction
d) `1.8xx10^(-2)` Nm at an anlge `340^(@)` with the +x direction
e) Zero
f) Zero
Force is zero in each case. Case (e ) corresponds to stable and case (f) to unstable equilibrium.