On 23 Oct 2007 20:19:34 GMT, Puckdropper
wrote:

I'm not sure about the question with the three lights and switch
bypassing one. They're going off a common misconception that electricity
follows the path of least resistance, but that cannot be true. Parallel
circuits would NOT work if it was. If I remember, I'll test it on a
breadboard later.

Puckdropper


The current in each branch of the parallel paths will be inversely
related to the resistance of the branch and directly related to the
resistance of the parallel branch. You can use Ohm's law (E=IR) to
derive the mathematical relationship.

If you assume the path through the switch has zero resistance (an OK
first approximation) then the current through the lamp would be zero.
As the resistance of the path through the switch increases, the amount
of current through the lamp would increase.

If you breadboard it, insert a variable resistor in series with the
switch. I predict that as you increase the resistance of the path
through the switch, the brightness of the lamp will also increase.

Tom Veatch
Wichita, KS
USA