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From: Jhumki Basu (sjbasu@hotmail.com)
Date: Tue Jun 24 2003 - 12:03:49 PDT 

From: "Jhumki Basu" <sjbasu@hotmail.com>
Subject: Current
Date: Tue, 24 Jun 2003 19:03:49 +0000
Message-ID: <BAY1-F11710Gai4omRX00001bdb@hotmail.com>

I've been taking a class where we've been tracking the current in wires in a
circuit by observing compass deflection. It's the kind of class in which you
don't think/believe anything unless you observe it directly or indirectly,
and we can't really ask questions about things other than what is directly
in front of us. So that's why I'm asking pinhole!

We've observed that the compass deflects approximately the same amount on
both sides of a bulb, suggesting that the charge flow rate is the same on
both sides of the wire connected to a battery.

Here's what I don't understand:
Electrons are moving through the wire and then supposedly "bump into" atoms
in the tungsten filament raising the tungsten electrons to higher energy
levels, which then "fall back" down, producing light. So don't the original
electrons in the wire lose some energy (i.e. the kinetic energy they lost
from transferring energy to the tungsten electrons)? Does this loss of
energy not show up in a slight reduction in current?

Maybe the loss shows up as a reduction in the moving back-and-forth
(vibrational) energy that all electrons possess. If this is true, why did
the electron have to be flowing in the first place to light the bulb? Isn't
the virbrational energy available without a current?

Second, my teacher says that since two light bulbs in a series circuit seem
to light at the same time, we should assume, from our observations, that
electricity travels instantaneously. But I can imagine that the electricity
travels too fast for us to observe its movement through the circuit. If the
bulbs are lighting instantaneously, then how can there be a directional
charge flow? Doesn't flow imply that time is passing?

Thanks, Jhumki

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