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# Re: [Phys-L] [**External**] Re: youtube the.tragic story of nikola Tesla

To use P=V*V/R you REALLY need (delta)V. The Voltage drop (delta V) for
the power company will only be 1 Volt (0.01 A * 100 Ohms) so the power for
the power company will be 1 V * 1 V / 100 Ohms = 0.01 Watts for the power
lines.

On Mon, Feb 22, 2021 at 7:43 AM Philip Keller via Phys-l <
phys-l@mail.phys-l.org> wrote:

Here's a follow up question that will reveal how little I understand about
AC.

Suppose I give that explanation to a student who then asks: Power = I*I*R
but isn't it also V*V/R? And when I use that equation, it suggests that
higher voltage is worse...

Since AC is only barely in my curriculum,, I never really have to come to
terms with this. And I have similar basic questions that reveal my
ignorance about transformers as well. But one at a time.

On Mon, Feb 22, 2021 at 8:20 AM Arlyn DeBruyckere <
arlyn.debruyckere@isd423.org> wrote:

Bill,

Consider powerlines with 100 Ω of resistance (not much). If a consumer
demands 1,000 Watts of power (1 kW, again not much) at 100 Volts (just to
make the math easy) they would need 10 Amps of current (P=VI). For 10
Amps
of current on the power company would waste 10,000 Watts on the power
lines
(P=I*I*R), delivering only 9% of the generated power. If instead the
power
company delivered the 1,000 Watts of power at 100,000 Volts the current
would only be 0.01 Amps and this 0.01 Amps of current will cause the
power
company to waste only 0.01 Watts, delivering 99+% of the generated power.
The issue with 100,000 Volts is that you'd need a "10 foot pole" just to
The solution is using transformers to change the Voltage with little
power
loss down to the usual 110-120 Volts because this spark is only a few
millimeters long.

On Sun, Feb 21, 2021 at 10:49 PM Bill Norwood via Phys-l <
phys-l@mail.phys-l.org> wrote:

No, I just need to understand why more electrical energy can be
transmitted when using ac

Bill Norwood

Sent from my iPhone

On Feb 21, 2021, at 11:10 PM, Marx, David via Phys-l <
phys-l@mail.phys-l.org> wrote:

Just to check, are you asking why we use AC instead of DC for power
transmission?

-----Original Message-----
From: Phys-l <phys-l-bounces@mail.phys-l.org> On Behalf Of Bill
Norwood
via Phys-l
Sent: Sunday, February 21, 2021 9:45 PM
To: phys-l@mail.phys-l.org
Cc: bnorwood111@gmail.com
Subject: [Phys-L] youtube the.tragic story of nikola Tesla

[This message came from an external source. If suspicious, report to
abuse@ilstu.edu<mailto:abuse@ilstu.edu>]

In this story of Tesla's life it is mentioned that a crucial reason
for
going with ac for the bulk of electric power transmission is the
ability
to
deliver (I think) twice as much power with pre-existing electric lines.

Could someone please explain how that works.

Thanks,

Bill Norwood

Sent from my iPhone
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