Question

state 1 difference between AC over DC why AC is preffered for long transmissions name the source for each

Answer 1

Used to be that AC was the only practical way of high voltage transmission which HV transmission was the only efficient means of long distance routing of power.

Now we have DC-DC converters that work at high voltage and high power. But they are quite expensive. They become practical as the AC reactive losses become great for really long distances and are also the practical solution to differing frequencies.

As DC-DC converter technology becomes cheaper, the distances that DC will become practical will come down.