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.
15)Why do we prefer potentiometer of longer length for accurate
measurement?
The longer is the length of the potentiometer wire, the higher is the accuracy because the potential drop on the wire per unit length decreases as the length of the Wire increases .Hence the potentiometer measures emf more accurately.