In the neutral point topic , what is the orientation of the magnet?
The orientation of the magnet here with respect to earth's magnetic field is the magnet is perpendicular to the earth's magnetic field.
16)The potentiometer wire must be long and of uniform
thickness- Why?
With increase in length the potentiometer becomes more sensitive. The fall of potential is proportional to the length of the wire only if the wire is of uniform thickness.