Electrical - Measuring Voltage.?

I have 4 questions about measuring voltage and the nuetral wire. I have worked alot installing fixtures, baseboard heaters plugs etc. I always shut the power off at the panel before I do any work. I think I understand how things work. I just want to confirm. Here we go. These are things I have kind of always... show more I have 4 questions about measuring voltage and the nuetral wire. I have worked alot installing fixtures, baseboard heaters plugs etc. I always shut the power off at the panel before I do any work. I think I understand how things work. I just want to confirm. Here we go. These are things I have kind of always wondered about.

From what I understand a voltage meter measures the difference between two points. For instance, a 110V outlet, if you touch the leads to the Black and White wire it reads 110V. This is because there is a 110V coming from the hot (Black) but the nuetral (white) has no power (0 volts). The difference between those two wires is the difference between 0 volts and 110 volts. Am I right about this - does it measure the voltage difference between two points?

Now if I have a circuit (say baseboard heater) that is 220. It has two hot wires and a ground and maybe a neutral. Each hot wire is bringing in 110V. If I measure across the hot wires (black and red) it will read 0 (or almost 0) volts. Because the voltage on each wire is equal (or almost equal) to each other - around 110 volts. Is this correct?

Another question is - Does the nuetral wire bring the electricity back to the panel? So if I removed a plug from the wall and exposed the wires. Now the wires are freely sitting there. Can I assume if I touch the white I would not be shocked. I know if I touch the black I would get zapped. Is this correct?

Final question in regards to the nuetral wire. When I turn a light switch on I have completed the curcuit. So now the power gets to the light bulb via the hot (black) wire. So the nuetral (white) which is hooked up to the bulb, is it returning unused power?
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