If a DC wire is cut?
If all you want to do ermine is polarity, then use a DC voltmeter of the appropriate voltage range. Or use a multimeter. Or use an LED test light. You can even use a potato!
What are you trying to accomplish? If you are trying to charge the battery you need lots more information about the DC adapter and the battery to do that. The simple answer is that you don't know enough to do it properly. You could start a fire and burn your house down... or up.
YOU NEED A BASIC TOOL CALLED DC VOLTMETER TO TELL ITS POLARITY ! MAKES NO HARM TO 12V BATTERY IF 12V ADAPTOR POSITIVE OUTPUT IS CONNECTED TO BATTERY POSITIVE TERMINAL. IF BY MISTAKE TO CONNECT 12V ADAPTOR NEGATIVE OUTPUT TO BATTERY POSITIVE TERMINAL, THAT SHALL DISCHARGE THE 12V BATTERY AFTER A DAY OR MORE AS THE POWER ADAPTOR IS POWERED UP.
Yes you can. I've done it alot. The wire with markings is the hot wire(positive)
yep, one wire will be 'marked' somehow .........................