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Re: units with zero?



At the risk of being too political, if asked "how much *money* are you
willing to donate to Bush for the upcoming election" I might respond
"zero dollars."

However, if asked "how much are you willing to donate to Bush for the
upcoming election" I might respond "zero"... that is... zero dollars,
zero time, zero votes.

On the non-political subject, I would say the above example is the
reason I prefer that the units are given with the value of zero. As I
stated in a much earlier post, if I ask about the potential difference
between two locations, I would distinguish between answers of zero
millivolts or zero volts or zero kilovolts or zero amps.

In the first three cases, it tells me what kind of meter was used. In
the third case, where a kilovolt meter was used, I might not want to
place my body across those two locations because there might be enough
potential difference to shock me, but it showed as zero on the kilovolt
meter. In the fourth case I definitely wouldn't put my body across
those two locations because the person telling me the potential
difference is zero doesn't know what he is doing.

I actually get this type of response fairly often. The student says, I
used a voltmeter and measured zero amps. That typically means they had
a multimeter, tried to measure a voltage (potential difference) with the
meter on the current range, blew the fuse in the multimeter, got a zero
reading because of the blown fuse, the circuit is still energized.

Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu