is this analogy is correct?

no.

w.

No it won't - if you connected it to earth, you need some way of getting the current to flow back (from earth) to the Zinc electrode.

In your circuit, I guess this is what the salt bridge is doing (enabling the current to flow back from where it started)

I'm having a nice time, seeing as you asked

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Bill Naylor
www.electronworks.co.uk
Electronic Kits for Education and Fun

why ?

if you connected it to earth, you need some way of getting the

is it really necessary.?

why do we need 2 wires to conduct electricity

I'm afraid that electric locomotives has single wire; i.e. singlephase

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  have a nice time

Why would you be afraid that locomotives "has a single wire" ?? (The other one being the rails )

Rheilly P

Idiot.

Try to trace the path of the electrons. If it doesn't make a closed loop through the supply, load, etc. then it does not make a circuit.

Tom Davidson Richmond, VA

g the

Electricity that doesn't require wires is called "lightning."

Trains that get their electricity from a third rail use the first two rails (which are connected together at various points) as part of the circuit. Electricians call this a "common" contact as opposed to the "hot" third rail.

Exactly what is it about the wiring of electric locomotives that frightens you?

Tom Davidson Richmond, VA

M.Parker Inscribed thus:

I'm afraid the earth is flat !

The rails are the other wire !

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Best Regards:
                Baron.

link

Thanks Tom; you are quick and informative.

Small thought Experiment:

A rotating Magnetic field will create a Current in a wire(I said a single long wire, not 2 pieces, no confusion here)

now, using this current in that single wire, how to make the bulb illuminates?

If I connect the one end of the wire to the '+' of the bulb and the '-' of the bulb to the earth.

By default, we are left with the other end of the wire as open.

There is Current in the wire by the effect of the rotating magnetic field, it would pass through the '+' of the bulb and there by to Tungsten(or whatever it is) and to '-' side of bulb there by to the earth.

then, why can't the Bulb illuminates? ==========

Procedure (2)

Instead of 1 single long wire, If I take 2 pieces of wires

One to the '+' of the bulb, other to the '-' of the bulb

at their both ends, if I joined them now the loop is closed.

If any rotating magnetic field produces the current in the wire the bulb will illuminates.

but, not in the first case, why?

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No the path isn't closed so no the bulb won't illuminate. You would also have to connect the copper electrode to earth as well.

It is possible to make an "apparently open" circuit work. For example some touch sensitive switches rely on capacative coupling of the human body to earth to close the circuit.

..in a loop of wire.

My one straight question..,

(q) why the path should be closed to illuminate the bulb?

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One of the more spectacular examples is with fluorescent tubes under pylons. Richard Box specialised in impressive dusk displays of this as artist in residence at Bristol University Physics dept.

Regards, Martin Brown

No, the rotating magnetic field will create an electromotive force or potential (measured in volts) on the wire. The amount of current (measured in amps) that flows in the wire will be a function of the load placed from end-to-end on the wire (completing the circuit).

(remainder snipped due to invalid thought experiment assumption)

Thanks. Same to you.

John

If it didn't have to be closed how would you turn anything off, or keep spare batteries charged? Think about it.

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You can\'t have a sense of humor, if you have no sense!

Lots of ways to answer that.

1) The coper electrode needs to recieve a supply of electrons or the chemical reaction in the battery stops.

2) The voltage across the bulb causes electrons to flow through it. If the right hand (+ve) side of the bulb was suddenly made open circuit, electrons flowing through the bulb would collect there (no place for them to go). This would reduce the voltage on that side of the bulb. Once the voltage across the bulb reaches zero no more electrons flow through the bulb.

so

Question - if you connect the copper electrode to earth, and the lamp to another earth 6 feet away, and the battery is 3VDC, would the lamp still light?

Thanks,

Michael

Given my 2 hands,

one hand holding the electric wire on the pole and the other touching the pole.

=> will I feel the electric shock or not ?

I touch only one wire, but not '2' as you people said for the illuminating of the bulb :-(

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  have a nice time

Are you wearing wellies and is it raining? If so, you might need some tissues.

Also: 'Do I feel lucky?'

These are questions you need to ask yourself

Still having a nice time - even after all these posts..

--
Bill Naylor
www.electronworks.co.uk
Electronic Kits for Education and Fun