Question

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 300 a at 120 v. what is the current in the 1.4×104 v line from the substation?

Answer 1

since all power is conserved, power remains the same
power = 300A*120V=36000W
Current = 36000W/1.4*10^4V=2.57A