How the leakage inductance of a transformer can be minimise by suitable design of the transformer?

Answer 1

A transformer is most efficient when all of the magnetic flux lines generated by the primary winding also pass through the secondary winding. This can be accomplished by interspersing the two windings, and by winding them around a high permeability soft iron core. Often it is also desirable to minimize the spread of the flux beyond the transformer. This reduces electrical interference with any nearby circuits, and reduces noise caused by vibration of nearby ferrous materials. This is done by making a complete loop of the iron core, providing a preferred return path for the flux lines. Additional shielding can be provided around all of that for more isolation.