किसी ट्रांसफार्मर की पूरे दिन की दक्षता (all-day efficiency) को किसके अनुपात के रूप में परिभाषित किया जाता है?

In which unit is the power rating of a transformer expressed?

In a transformer, it is generally preferred to wind the low-voltage winding close to the core and the high-voltage winding over the low-voltage winding. What is the primary advantage of this type of arrangement?