A small rectangular coil ABCD contains 140 turns of wire. The sides AB and BC of the coil are of lengths 
and 
respectively, as shown in the figure below.
The coil is held between the poles of a large magnet so that the coil can rotate about an axis through its centre. The magnet produces a uniform magnetic field of flux density 
between its poles. When the current in the coil is 
, the maximum torque produced in the coil is 
.
For the coil in the position for maximum torque, state whether the plane of the coil is parallel to, or normal to, the direction of the magnetic field.
For the coil in the position shown in the figure above, calculate the magnitude of the force on
side AB of the coil,
side BC of the coil.
Use your answer to (b)(i) to show that the magnetic flux density between the poles of the magnet is 
.
.
