In a circuit, what causes current to go from L1 to L2?

[fourthindiana]

The photograph above this sentence is a photograph of a simple 2 leg circuit of alternating current with a light switch and a light bulb. I know how alternating current constantly switches direction from line 1 to line 2 and then goes from line 2 to line 1, etc. In the diagram in the above photograph, when the switch is closed, if the current goes from line 1 to line 2 first, what causes the current to flow from Line 1 through the switch and into the light bulb (lighting up the light bulb) and to Line 2? If the current goes from line 2 to line 1 first, what causes the current to flow from line 2 through the switch and into the light bulb (lighting up the light bulb) and to line 1?

I have a feeling that the answer somehow involves electron's attraction to positive charges, but I don't know how it would work since there are negatively charged electrons in both the wire of line 1 and line 2.

Is it the case that when you have a 2 leg circuit, one leg always has more electrons than the other and the current first flows from the leg with more electrons to the leg with less electrons?

 

[Drakkith]

In the diagram in the above photograph, when the switch is closed, if the current goes from line 1 to line 2 first, what causes the current to flow from Line 1 through the switch and into the light bulb (lighting up the light bulb) and to Line 2?

The applied voltage from the power source.

If the current goes from line 2 to line 1 first, what causes the current to flow from line 2 through the switch and into the light bulb (lighting up the light bulb) and to line 1?

Same answer. The applied voltage from the power source.

I have a feeling that the answer somehow involves electron's attraction to positive charges, but I don't know how it would work since there are negatively charged electrons in both the wire of line 1 and line 2.

No separation of charges is necessary. A changing magnetic field can induce a voltage in the circuit, causing current flow, yet the electrons have no isolated positive charges anywhere in the circuit to be attracted to.

Is it the case that when you have a 2 leg circuit, one leg always has more electrons than the other and the current first flows from the leg with more electrons to the leg with less electrons?

No, circuits don't work by changing the number of charges in one area as to attract/repel electrons. A change in the local electromagnetic field is generated by your power source in such a way as to cause charges to move. Explanations for this range from very simple (but very shallow) to extremely complex.

 

[fourthindiana]

The applied voltage from the power source.
Same answer. The applied voltage from the power source.
No separation of charges is necessary. A changing magnetic field can induce a voltage in the circuit, causing current flow, yet the electrons have no isolated positive charges anywhere in the circuit to be attracted to.
No, circuits don't work by changing the number of charges in one area as to attract/repel electrons. A change in the local electromagnetic field is generated by your power source in such a way as to cause charges to move. Explanations for this range from very simple (but very shallow) to extremely complex.

I don't know exactly what you mean when you say that a changing magnetic field can induce voltage in the circuit.

In the diagram in the attached photograph, is it the case that when the switch is closed, current will flow from Line 1 to Line 2 and current will flow from line 2 to line 1 simultaneously? If not, what determines whether the electrons will first flow from line 1 to line 2 or from line 2 to line 1?

 

[Drakkith]

I don't know exactly what you mean when you say that a changing magnetic field can induce voltage in the circuit.

https://en.wikipedia.org/wiki/Electromagnetic_induction

In the diagram in the attached photograph, is it the case that when the switch is closed, current will flow from Line 1 to Line 2 and current will flow from line 2 to line 1 simultaneously?

No. Current will only flow in one direction at a time.

If not, what determines whether the electrons will first flow from line 1 to line 2 or from line 2 to line 1?

The polarity of the applied voltage at the time you close the switch.