question about current flow in an electric circuit?

If you are grounded, YES, you can get a shock. And yes, if you touch one lead to the nutural and the other to ground, you will get a reading but most likley it will trip the breaker.

The equations for describing those flows are similar in nature: for water bypass use the continutiy equation: Q=VA the position Q is the quantity of fluid, A is the area of the conductor and V is the speed of bypass, persons versed in electric powered theory will immediaely recognize that it really is a fact of Ohm"s regulation E = IR mechanical engineers might want to be sure a similarity with s = at or F= ma at the same time as civil engineers will keep in mind rigidity = M x section modulus. All of it really is a elementary indication that mechanics is mechanics in spite of the cloth.

With power on to a circuit but nothing in use there is 0 potential on the neutral.

Maybe. I'll get back to that in a moment.

When the current is flowing (through something turned on) the neutral carries the return load. So if you had one 100 watt lamp on, that would be about .8 amps. (watts / volts = amps, or 100w / 120v = .8a)

Now then, there are circumstances where a neutral is allowed to be Shared by 2 hots on Different Phases in the panel. In that case the load on the neutral is the Unbalanced load. Say you have a 100 watt lamp on A phase and a 60 watt lamp on B phase and a shared neutral. You have .8 amps on A and .5 amps on the B and .3 amps on the neutral. So turning off one circuit doesn't kill all of the load on a Shared Neutral. This is one of the ways folks get into trouble and injured/killed when working on branch circuits.

However, if BOTH of those loads happened to be on the SAME phase the neutral would now be carrying both loads or 1.3 amps. And again, turning off one circuit would not kill all current on the neutral. This is known as a "back feed", a potentially dangerous/deadly condition.

Folks create problems all the time without knowing it as a result of moving breakers around, or "Willy Nilly" adding wires to existing circuits.

This is why "they send Us to School" to learn this kind of stuff.

So, Yes you get shocked by the "neutral", and yes it will read current.

If the appliance is on you could get a shock from, and a meter would show current in, the neutral wire. With the exception of those appliances that have indicator lights and "vampire" drains when they are shut off, the current from the load line would be stopped when the appliance is off.

You just need to learn basic electricity. The link goes to a free course.

http://jacquesricher.com/NEETS/