Electricity is distributed from electrical substations to neighborhoods at 1.4×104 VV . This is a 60HzHz oscillating (AC) voltage. Neighborhood transformers, seen on utility poles, step this voltage down to the 120VV that is delivered to your house.

Part A
How many turns does the primary coil on the transformer have if the secondary coil has 100 turns?

Part B
No energy is lost in an ideal transformer, so the output power Pout from the secondary coil equals the input power Pin to the primary coil. Suppose a neighborhood transformer delivers 280 A at 120 V. What is the current in the 1.5×104 V line from the substation?