use a potential divider with R2 and R1 being 100 ohms
12 volts
No. 12 volts peak to peak would be 6 in the positive polarity and 6 negative polarity. Simply saying 12 volts AC would be 12 volts in each polarity or 24 volts peak to peak
12 volts
It is 12 volts.
Yes, that is safe.
6 volts
12 volts
600 Volts
For radios 6 volts, for cars 12 volts, for large vehicles 24 volts, for submarines 220/440 volts.
12V.
2 volts
When we see 6 mv in a statement, it usually means 6 millivolts. That's 0.006 volts, or 6/1000ths of a volt. Don't confuse it with 6MV, which is 6 Megavolts, or 6 million volts!