hTTi

As of this week I finally understand the point of electron volts.
Same scale as an atto joule. Didn't understand why they didn't just use aJ instead of eV
Now I do.
Same reason cosmologists live a light speed of 1. 1 lightyear/year

It all started with a joke:

Why did the quantum mechanic smoke?

MadAxeMurderer wrote: ↑Mon Mar 30, 2026 9:30 am Why did the quantum mechanic smoke?

To make light rays visible?

MadAxeMurderer wrote: ↑Mon Mar 30, 2026 9:30 am As of this week I finally understand the point of electron volts.
Same scale as an atto joule. Didn't understand why they didn't just use aJ instead of eV
Now I do.
Same reason cosmologists live a light speed of 1. 1 lightyear/year

Same reason we use Watt-hrs, assuredly otherwise a completely stupid unit. The unit is that is most annoying is the SI's adoption of candela, which serves only display makers. That's in contrast to Kelvin, gram, centimeter and ampere, all of which are physically motivated.

The best article I've read about units in years is "Temperature as Joules per Bit": https://pubs.aip.org/aapt/ajp/article/9 ... es-per-bit It's a quick read for those interested in this topic.

-- Alison

alison wrote: ↑Mon Mar 30, 2026 10:29 pm Same reason we use Watt-hrs, assuredly otherwise a completely stupid unit.

When you buy ..., you need to specify the required seconds/ohm.

Name the product "...".

Franklan wrote: ↑Mon Mar 30, 2026 11:14 pm
When you buy ..., you need to specify the required seconds/ohm.

Name the product "...".

Ohms = Volts/ampere, and ampere*seconds = coulombs. Thus seconds/ohm = coulombs/volt, which is a capacitance. What kind of capacitor is the question? I'll take a wild guess and say a flash-lamp for photography.

-- Alison

alison wrote: ↑Tue Mar 31, 2026 3:03 pm Ohms = Volts/ampere, and ampere*seconds = coulombs. Thus seconds/ohm = coulombs/volt, which is a capacitance. What kind of capacitor is the question? I'll take a wild guess and say a flash-lamp for photography.

Indeed, Farad=Seconds/Ohm

Why did the quantum mechanic smoke?
He/she was forced to use SI units.
Forcing a defenseless electron through 1 volt was considered too brutal for a civilised society.

Franklan wrote: ↑Mon Mar 30, 2026 10:55 am To make light rays visible?

Very nice!

Smoke enables visualization of sub-PHz photon flux via scattering.

alison wrote: ↑Tue Mar 31, 2026 3:03 pm

Franklan wrote: ↑Mon Mar 30, 2026 11:14 pm
When you buy ..., you need to specify the required seconds/ohm.

Name the product "...".

Ohms = Volts/ampere, and ampere*seconds = coulombs. Thus seconds/ohm = coulombs/volt, which is a capacitance. What kind of capacitor is the question? I'll take a wild guess and say a flash-lamp for photography.

-- Alison

Wow Alison I did not expect an alternative view of electro dynamics Yes "dt/R = sigma(I)/V" formally describes the above. I could well have decimated time inappropriately?

That's not a revelation. You probably haven't invented the eV of transmission lines. If you had then Maxwell/Farady or Nyquist/Shannon would have too.

Or your quoted article. But it's an intriguing alternative reality just like cosmologists too genuinely love c=1

Now a kwH is a human oriented unit like Fahrenheit is human oriented, Centigrade water oriented, and kelvin physics oriented.
And all named after people as if of course the Joule

The Gigajoule would be how many Wh.
Or the Megamile. The battery needed to drive 1M miles if the USA has a say in new units.