A friend of mine who knows I believe in God but also put faith in

Wingnuts

A friend of mine who knows I believe in God but also put faith in science that has been proven ordered me this t-shirt (see attachment).

And it's really sweet, but I don't want to wear something if I don't understand it...

I went searching, but the closest thing I've found so far is a wiki document for maxwell's equations, but they aren't quite the same as what is on this shirt.

Would someone kindly explain this, and is it a standard equation, or is it just one relating to lighting or electric light or light emitted by stars or what?

Thanks in advance for humouring my ignorance...

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Doc Al

That's what they are, a version of Maxwell's equations. Solutions to those equations include electromagnetic waves, such as light.

tiny-tim

Hi Wingnuts Welcome to PF!

Yes, they're the integral form of the four Maxwell's equations, in free space (so ε_r = µ_r = 1).

See section 3 of the PF Library article …

the differences are:

i] dA and ndS are the same thing, the vector representing a small element of area

ii] dS is wrong, it should be a small letter, either ds or dl (small element of distance) (S should mean a surface)

iii] Φ is the flux through the whole surface … so instead of ∂/∂t of an integral of E (or B) over surface S, your T-shirt has ∂/∂t of the flux of E (or B) through S … same thing

Hassan2

Here is the T-shirt: with the equations in differential form!

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Khashishi

tis not wrong to use a capital letter, just less conventional.

Redbelly98

It sounds like that T-shirt is perfect for you.

p.s. Welcome to Physics Forums!

jim hardy

Good for you.

I dont remember any commandment saying "Thou Shalt Not Think" .

Great message !

vanhees71

The integral form is correctly written in the special case of volumes, surfaces and boundaries of these at rest. The local (differential) form in the other posting is general. The only difference is due to the choice of units, which in the Ops case is the SI and in the white shirt's case in Heaviside-Lorentz units with [itex]c=1[/itex]. I'd prefer the shirt. Even better were to write the equations in relativistic covariant form and Heaviside-Lorentz units since God for sure loves natural units and even more symmetry (and symmetry breaking, but this latter ingredient of the Standard Model not in the QED sector).

Wingnuts

Thanks to everyone for the warm welcome and for the very helpful replies!

One thing is immediately clear: I know now what it's saying (because it's now been confirmed by the 'experts': the internets have, yet again, proven to be useful ) however, I still am not much further to *understanding* it. So, I have a steep learning curve ahead. Time to hit DeSlegte for a second hand physics 101 book.

This analysis, based on the following link to the library document, confused me. The dS is also written with a capital letter 'S' there too.

Is Khashishi correct that it is just less conventional to write with a capital S, or is S really 'surface', and therefore, not appropriate? Perhaps a vote is needed, or is that just pointless pedantry, because those who can read should know which one it is within context?

Cheers!

Wingnuts

Thanks! Normally I would have to clarify my definition of 'proven', but I get the feeling that won't be necessary beyond saying that cargo cultists need not apply. To piggyback on Jim Hardy's delightful negative expression there, one of the actual commandments might be, "Thou shalt not produce nor accept dogmatically charged 'results'"

Wingnuts

You're all such a congenial bunch. Thanks!

I strongly encourage you to do just that. If you do, I'll get that shirt too and then will have options. For calm days, regular days and complex days (given your description, for when I'm feeling especially rebellious ) Seriously!

tiny-tim

Hi Wingnuts!
No, in the Library article, every 'S' without a "dot" represents an area (with n dS = dA).

On the T-shirt, every 'S' comes with a dot", and represents a length, where the Library has "l".
If a friend gave you a T-shirt with "e = mC²", would you say that that was "just less conventional"?

Wingnuts

Ha ha ha. Very funny... Stepped right into that one, right? Now I see, the obvious (to me) clues as being c=1 and 'relativistic co-variant form'. No? Or have a I just made an even bigger fool of myself? Well, I did say I was clueless, which was an open invitation. I pray your next prey to be a little more worthy.

Now that I know the culture, I'll be a bit more careful where I tread.



Thanks for the help, guys.