Re: Energy vanishing into air? (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 17 Jan 2004 23:21:45
From: David Dameron <ddameron@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Energy vanishing into air? (fwd)

At 02:19 PM 1/17/04 -0700, you wrote:
>Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Sat, 17 Jan 2004 11:54:14 -0500
>From: Alfred Erpel <alfred@xxxxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Energy vanishing into air?
>
>
>
>Howdy All,
>
>    Imagine an air variable capacitor with plates fully engaged and the
>capacitor fully charged.
>
>    Let's use the example of .001µF charged to 10,000 volts. Stored energy =
>joules = .5CV^2 = .05 watt=seconds.
>
>    What happens to the energy of the fully charged capacitor when the
>plates are rotated to the 0µF capacitance position?
>
>Regards,
>
>Al Erpel

The energy is still there, as there still is some capacitance, even if as
"self-capacitance" of the plates. Actually the energy is increased, as work
is done separating the plates and this is converted to electrostatic
energy, 0.5CV^2, using Q = CV = constant.
-Dave D.
>
>[Potential energy.  It would take that much energy to rotate the cap
>plates to the 0uF position (barring friction losses), and rotating them
>back would convert the energy back from potential to the energy stored in
>the electrical field.  SRR]
>
>
>