The couple acting on a closed loop is given by `tau=NiAB`
`sin theta`
Where, N=number of loops, A=area of loop, B=magnetic
field and `theta`=angle between magnetic field and normal to the
surface of the loop.
Here `N=1, i=0.1A, B=5xx10^-2T, theta=90^@` and `A=1/2(Basexxheight)=1/2 (0.02xx0.01732)=1.732xx10^-4 m^2`
`:. tau=1xx0.1xx(1.732xx10^-4)xx(5xx10^-2)xx1`
`=8.66xx10^-7Nm`