The h Bar

0celo7

5:00 PM

@ACuriousMind Idk why someone starred that, but can you please change "charger" to " charge?"

ACuriousMind

@Fawad What?

Fawad

@ACuriousMind sorry,wat? Nevemind…

0celo7

@ACuriousMind Thanks.

ACuriousMind

@Fawad why would you think I was about to "charge" (what does that even mean?) or suspend skullpetrol?

0celo7

charge him with treason @ACuriousMind

Fawad

5:04 PM

Nevemind,I read wrong…XD

Yashas Samaga

@ACuriousMind why aren't totally wrong, personal theory answers deleted?

skullpetrol

Made It ma! top of the world!

►

Yashas Samaga

Last year when I had flagged answers for technical accuracies, it was declined. The reason given was " declined - flags should not be used to indicate technical inaccuracies, or an altogether wrong answer ".

-2

A: If Energy can be converted into mass, why can it not be converted into charge?

I believe that this question is still valid through logical deductions because of the fact that charge can be converted to energy using the following equations: $$E = mc^2$$ $$V = \frac{E}{Q}$$ Therefore according to current physical knowledge, the following should be applied: $V = \frac{mc^2}...

ACuriousMind

@YashasSamaga Because, much as it pains me, it is policy to not delete wrong answers. The accuracy or usefulness of answers in the SE model is decided by up- and downvotes, not single-handedly by users with moderatorial powers.

Yashas Samaga

The answer is soooooo wrong.

0celo7

5:08 PM

@ACuriousMind loo

I meant lol

Yashas Samaga

That terrible horrible wrong answer is visible to whoever visits that question.

ACuriousMind

For further discussion of this point, see meta.physics.stackexchange.com/q/5244/50583, meta.physics.stackexchange.com/q/2677/50583, meta.stackexchange.com/q/264293/263383, meta.stackexchange.com/a/5222/263383

satyatech

@EmilioPisanty what is the structure of a muonic atom

@Sid

ACuriousMind

Also, can you imagine the battlefield meta would become if we started deleting wrong answers? No, thanks.

@satyatech please do not randomly ping people unless you have reason to believe they are interested in answering your question.

satyatech

@Sid can you answer my question

@ACuriousMind sir how could I know whether they are really interested to answer, should I call them?

Fawad

5:14 PM

in Mathematics, Oct 20 '16 at 13:02, by Balarka Sen

@Ramanujan Please don't ping random people to answer your questions.

satyatech

@ACu

Fawad

This is common for new users,so @satyatech first you need to know if someone is interested to help you

ACuriousMind

@satyatech As I said, please don't ping them unless you have reason to believe they are interested in answering your question. If you don't know whether they're interested, don't ping them.

Fawad

And that message was starred by 11 people :P

Yashas Samaga

@satyatech and you also must try finding out trivial things yourself. I am pretty sure wikipedia would have had an answer for your question.

satyatech

5:16 PM

@YashasSamaga I searched for that but couldn't find so I have doubt

ACuriousMind

Anyone who wants to answer your question can read it in the transcript and will answer it. Although I believe almost no one will answer a question that you could've tried to answer by doing a simple Google or Wikipedia search.

Yashas Samaga

@satyatech en.wikipedia.org/wiki/Exotic_atom#Muonic_atoms

skullpetrol

Oxides of each.

That's why they used commas.

Fawad

Sure?Then ok

skullpetrol

Yes.

satyatech

5:22 PM

@YashasSamaga sir in my book there is a qn that if a proton absorbs a muonic then find the radius of the first Bohr orbit of this atom, that is what I could not figure out ,and the information given in Wikipedia is not in my level ,so please clarify.

Yashas Samaga

You needn't address me as sir for two reasons. 1. I don't need that much respect lol

2. classified

satyatech

2.What is classified

Yashas Samaga

and I honestly don't think using a muon instead of an electron would significantly alter the equations you obtain using the Bohr model

skullpetrol

Just like: the lighter shades of blue, green, and red are hard to see for some people. @Fawad means each color, right?

Yashas Samaga

@satyatech muons are relatively heavy though

satyatech

5:26 PM

So muon is like a electron with mass 207 * electron mass ,it will revolve around that proton @YashasSamaga

Mostafa

17

Q: Opt-in to be always pingable to answer questions

Original idea: List of users with specialities who are willing to be pinged--should we do this? This is a place where users can opt in to be pinged by other users regardless of their chat status. What sort of pings is this for? Try to keep the ping related to P.SE . Some example uses of...

@satyatech You can always ping these users.

ACuriousMind

@Mostafa That's an ancient meta post that to my knowledge no one has used for years

Yashas Samaga

@satyatech a proton still has 100 times more mass

@satyatech moreover, you are using the bohr model, the electromagnetic forces are way more powerful than gravitational forces (if you were thinking about this)

ACuriousMind

Almost none of the users is a regular in chat, you can't even ping them here if you wanted to

skullpetrol

They should come here!

Mostafa

5:28 PM

@ACuriousMind I doubt anyone has ever used that post :)

So I used this chance to promote it.

satyatech

@YashasSamaga Bro, my teacher gave me knowledge not ever mess with Newtonian mechanics inside quantum mechanics

Yashas Samaga

Bohr theory is not QM

Physics Meta

0

Q: Open justice v secret police

I'd like to raise a point for discussion. It concerns moderation, and I think the best way I can summarise it succinctly is open justice v secret police. It came up on this post, where DavidZ said "the moderators do not discuss individual suspensions in public". I think there's a degree of secre...

discussion moderation suspensions

Yashas Samaga

@satyatech It is classical mechanics.

skullpetrol

This chatroom needs more promotion imho

Yashas Samaga

5:31 PM

Is this question on-topic?

0

Q: Long range forces?

A force/field which depends inversely on the square of the distance of the source from the point of interest (like electric field depends on 1/r², where r is the distance between the the source charge and the test charge) is said to be 'long range'. Why?

field-theory

Emilio Pisanty

@satyatech what ACM said.

Sid

Um, I am sorry to disturb, but I got pinged here by someone...

skullpetrol

No disturbance, welcome.

DanielSank

@Sid So... why not just read the ping?

Sid

someone apparently wanted me to answer a question, yet they have not linked the question

DanielSank

5:41 PM

This is an interesting question

-1

A: February 20th Ask Me Anything with heather: Question Pool

I note your interest in quantum computing. I have a deep interest in physics, but I'm a IT guy by profession, and I've taken careful note of the way digital electronic or "ordinary" computing has advanced in leaps and bounds over recent decades. Advances in computing has changed our lives, for th...

I'd be interested to hear the response during @heather AMA.

Careful. Calling a user an idiot can get you suspended.

@YashasSamaga I have added some comments.

ACuriousMind

@YashasSamaga Seconding DanielSank, please do not call other users "idiots".

DanielSank

@ACuriousMind Funny how that exact word came up here after our previous discussion...

Should we rather characterize the user in question with the phrase {often makes unsubstantiated claims and refuses to engage in discussion about those claims in good faith}?

If so, what's really wrong with shortening that to "idiot"?

(I'm only half kidding. It's kind of an interesting question about the utility of language)

obe

@DanielSank LOL

DanielSank

@obe It is a good question. John's own opinions and recurring badgering of this issue aside, "how long will you be interested in a line of scientific inquiry that yields nothing useful to humanity" is a really good question that we should all ask.

ACuriousMind

@DanielSank "Idiot" can have many other shades of meaning, I would not say it's a "shortening" of what you said before, in particular it contains a degoratory implication the target is of exceptionally low intelligence

DanielSank

5:52 PM

@ACuriousMind Indeed. I wonder if there's an English word for the phrase in {}'s above.

English often surprises us with its rich set of nouns an adjectives.

Yashas Samaga

Uhm, I never called him an idiot. lol

Well, I did mention but it wasn't... uhm... idk what to say

obe

@DanielSank well sometimes it's not obvious when a line of scientific inquiry will lead to something useful for humanity. but most of the time that's irrelevant because science isn't all about useful applications.

DanielSank

@obe I think science is about useful applications.

obe

it is but not all of it is dedicated to that.

DanielSank

In some way, I really think it is.

...but only in the sense that I think, because we are living creatures, that everything we do is about useful applications... by construction.

obe

5:59 PM

to rephrase what you're saying, don't you think it's better to say that all of science will eventually lead to useful applications that's why in a way you can say that it's all about useful applications.

Mostafa

@DanielSank He's posted the same question in your AMA meta post. Did you actually discuss it?

DanielSank

@Mostafa I don't remember!

obe

because somethings just don't have direct real world applications.

DanielSank

I remember him asking, but I don't remember if I answered.

@obe I think our species does science because it has aided our survival.

Why on earth was that message starred?

Weird.

Mostafa

@DanielSank What?! :) How's that even possible? to remember other's act but not yours.

Weird.

obe

6:02 PM

@DanielSank I agree but not all science directly aids our survival yet we still do it.

DanielSank

@obe It's a bit like sexual selection. Some birds have ridiculously long tails that attract mates but are wholly unhelpful for survival.

Possibly, in the limit of small tails, a larger tail is actually better.

Natural selection is very interesting. Have you read The Selfish Gene?

obe

I guess you could say that we're driven to do science because we have a natural need to learn more about the universe we live in, which in turn increases our chance of survival because the more you learn about your surroundings the better your chances of survival.

@DanielSank nope but I am a big fan of dawkins.

DanielSank

@obe Right, it's simple. We do science, we get cars, planes, tools, etc. Population goes up. Done.

obe

xD

btw have you been to iceland before?

DanielSank

This even explains why scientific/industrial cultures expand more than those who live as foragers, etc.

@obe Nope. Why?

obe

6:08 PM

I'm thinking of going there real quick during reading week.

Mostafa

@DanielSank By the way, yesterday I was taking a look at your PhD thesis.

One thing especially caught my attention: It has the longest and most comprehensive Acknowledgments section I've ever seen!

obe

there are these blue caves made of ice there

really cool

anonymous

@DHMO Hello. You there ? :D

DHMO

yes

DanielSank

@Mostafa Yes. I felt it important to put into writing how the people in my life contributed to my success.

anonymous

6:10 PM

I have a problem on complex numbers. Want to try ? I got stuck at the end. Here it is : >If $z_{1},z_{2},z_{3}$ are three complex number such that $|z_{1}| = |z_{2}| = |z_{3}| = 1$

>and $\displaystyle \frac{z^2_{1}}{z_{2}z_{3}}+\frac{z^2_{2}}{z_{3}z_{1}}+\frac{z^2_{3}}{z_{1}z_{2}} = -1.$Then possible values of $|z_{1}+z_{2}+z_{3}|$ are ?

Seeing you online after a long time :)

DHMO

So $z_1 = e^{i\theta_1}$ etc

DanielSank

@Mostafa Did you read the first chapter? A few readers (including non-physicists) have commented that they found it useful.

anonymous

@DHMO Yeah, I tried that.

DHMO

@anonymous $\exp(i(2\theta_1-\theta_2-\theta_3)) + \exp(i(2\theta_2-\theta_3-\theta_1)) + \exp(i(2\theta_3-\theta_1-\theta_2)) = -1$

Let $\theta_0 = \theta_1+\theta_2+\theta_3$

$e^{3i\theta_1} + e^{3i\theta_2} + e^{3i\theta_3} = -e^{i\theta_0}$

DanielSank

@obe That's beautiful.

anonymous

6:13 PM

@DHMO Looks good so far

Mostafa

@DanielSank I read section 1.1 (up to page 10).

Yashas Samaga

help me

But it will exist.. However small it may be..Won't it..? — Bhavya Sharma 33 secs ago

obe

@DanielSank yep!!! but it's 50 50 if you get to see them even if you go there, they melt all the time depending on the weather since it's always borderline freezing there only.

anonymous

@YashasSamaga How?

DHMO

@anonymous $\exp(i\theta_0) + \exp(3i\theta_1) + \exp(3i\theta_2) + \exp(3i\theta_3) = 0$

Yashas Samaga

6:16 PM

@anonymous look at the comments

debate in progress

obe

this video shows it pretty well

anonymous

@YashasSamaga I saw. Just tell them that infinity is a theoretical concept :)

obe

"The Crystal Cave" - Iceland Ice Cave (extended cut)

►

so coooool

Yashas Samaga

I told that infinity is not a number, it does not exist.

skullpetrol

Not a real number.

anonymous

6:18 PM

@DHMO Ah. Okay? Then?

DHMO

@anonymous I'm still thinking lol

skullpetrol

No real number exists called "infinity." @YashasSamaga

Slereah

there's infinity on the extended real line

skullpetrol

Did I say "extended"?

anonymous

@DHMO I give you four options and one or more of these are the correct options for the question: (A) 1 (B) 2 (C) 3 (D) 4

Mostafa

6:20 PM

@DanielSank and I found it very interesting.

Even the acknowledgments! (yes I read that too)

Yashas Samaga

I am arguing against Bhavya because she said force is NOT zero at infinity.

She claims it is really really tiny.

I am claiming the force is really really really tiny at infinity - epsilon

anonymous

@YashasSamaga Just leave it :P Vote and move on. They will learn it in their maths class.

DHMO

@anonymous I have no idea

Yashas Samaga

but zero at infinity

anonymous

@DHMO Use triangle inequality. Hint 1. :)

@YashasSamaga If you are interested you can try the complex number problem I posted above!

It is a good one

12 mins ago, by anonymous

I have a problem on complex numbers. Want to try ? I got stuck at the end. Here it is : >If $z_{1},z_{2},z_{3}$ are three complex number such that $|z_{1}| = |z_{2}| = |z_{3}| = 1$

>and $\displaystyle \frac{z^2_{1}}{z_{2}z_{3}}+\frac{z^2_{2}}{z_{3}z_{1}}+\frac{z^2_{3}}{z_{1}z_{2}} = -1.$Then possible values of $|z_{1}+z_{2}+z_{3}|$ are ?

DHMO

6:23 PM

@anonymous wait, if four unit vectors add up to nothing, then they form a rhombus!

skullpetrol

But you can not assign a single real number to "infinity." @YashasSamaga

anonymous

@DHMO I meant the inequality |a+b+c+.....| <= |a| + |b| + |c| + .......

You know that. Right?

DHMO

sure

anonymous

That will help you eliminate one option

skullpetrol

Infinity is not a unique real number @YashasSamaga

anonymous

6:24 PM

But that's not enough

DHMO

@anonymous Sorry I need to go

anonymous

@DHMO Sure. See you soon. And we will discuss the problem then!

Yashas Samaga

where is it?

anonymous

@YashasSamaga What?

Yashas Samaga

nvm found

......

multiply the first term by $z_1$

second term by $z_2$

third term by $z_3$

leme write it

instead of spamming

anonymous

6:28 PM

Yes. Go on :)

skullpetrol

:)

Yashas Samaga

Do you know the condition for equilateral triangle in the complex plane if z1, z2, z3 are the three vertices?

anonymous

Yes I know. Summation of $z^2$ terms equal summation of $z_1z_2$ terms

Basically : $z_1^2+z_2^2+z_3^2=z_1z_2+z_2z_3+z_1z_3$

Yashas Samaga

is the answer 1?

and 4

anonymous

No.

1,4 is definitely not correct choice

Hint: Use triangle inequality to eliminate one option

user228700

6:36 PM

Dammit, where is @JohnR when I have to tell him about how one of the Vlogbrothers replied to my comment aaah?!

Yashas Samaga

$4 = |z_1 + z_2 + z_3||equi-trangle-formula|$

anonymous

@YashasSamaga Whatttttt??????

Yashas Samaga

I rewrote the constraint

anonymous

What type of formula is that :P

@YashasSamaga Which constraint?

Yashas Samaga

$4 = |z_1 + z_2 + z_3||z_1^2 + z_2^2 + z_3^3 -z_1z_2 - z_2z_3 - z_1z_3|$

I rewrote \frac{z^2_{1}}{z_{2}z_{3}}+\frac{z^2_{2}}{z_{3}z_{1}}+\frac{z^2_{3}}{z_{1}z_{2}} = -1 as ^

anonymous

6:38 PM

@YashasSamaga Ok. Now it makes sense.

Yashas Samaga

I see 4 and 1 only :/

or I'm doing something stupid

anonymous

Three unit vectors when added can NEVER give magnitude 4.

Yashas Samaga

interesting

my constraint is wrong

oh interesting, I got that constraint in my second attempt

you need integers, right? or real numbers?

not a range?

anonymous

@YashasSamaga If you can find range that is more preferable. But if you manage to find only the correct options even that is okay.

Yashas Samaga

range is obvious

0 < answer <= 2

anonymous

6:44 PM

@YashasSamaga How?

Why <=2?

Yashas Samaga

that was obvious from the start itself -_-

anonymous

@YashasSamaga It is not so obvious to me

Yashas Samaga

It is even more obvious from my new constraint.

anonymous

Please explain your approach

Yashas Samaga

the first step was as I said intiially

multiply the each numberator with the correct term

you get sum of cubes on one side and product of the numbers on the other side

anonymous

6:46 PM

Hmm. Then ?

Yashas Samaga

you bring the z1z2z3 product to the elft side

anonymous

Then what? How did you get <=2 ?

I will send a pic

Okay

6:53 PM

@YashasSamaga Yeah. I get that. But why is range between 0 and 2?

(As you claimed)

Yashas Samaga

|z_1 + z_2 + z_3| cannot be 3

skullpetrol

Start looking for a new gf? @Slereah

anonymous

Yeah. So ?

@YashasSamaga

Yashas Samaga

I screwed it up again

I realized when I wrote it down

anonymous

6:55 PM

And why it can't be 3 ? @YashasSamaga (I want to know your reasoning )

Yashas Samaga

the only way it can be 3 is if you use 1,1,1 or -1,-1,-1

it is obvious that they won't satisfy the condition

anonymous

@YashasSamaga Any three parallel unit vectors when added give 3 as magnitude. So those two are not the only options.

Yashas Samaga

You have to ensure that |z_x| is also 1 :)

so the other options won't work

anonymous

@YashasSamaga I said "unit" vectors.

Yashas Samaga

where x = 1, 2, 3

anonymous

6:58 PM

Take i,i,i and -i,-i,-i for example.

They add up to give magnitude 3

Yashas Samaga

parallel = 1, 1, 1 or -1, -1, -1 or i, i, i or -i, -i, -i

these don't work

anonymous

@YashasSamaga No, these arent the only options.

Yashas Samaga

-_-

anonymous

Take $e^(i\frac{117\pi}{737}),e^(i\frac{117\pi}{737}),e^(i\frac{117\pi}{737})$

Even these add up to give 3

Yashas Samaga

They won't add up to 3 -,-

oh wait it does

they are equal

anonymous

7:01 PM

@YashasSamaga -__________-

Yashas Samaga

:D

looks like I need to revise algebra

anonymous

So a solid reason is still missing :)

Yashas Samaga

ok z1 != z2 != z3

all three cannot be the same together

anonymous

@YashasSamaga What is the reason for it?

Yashas Samaga

you can substitute and check, it won't satisfy

so it rules out any parallel or anti parallel vectors

so there goes 3 :)

anonymous

7:02 PM

Good. Now you are speaking sense :)

Yashas Samaga

:P

anonymous

Now the range

@YashasSamaga Well it rules out only parallel vectors. Not anti-parallel.

Yashas Samaga

if you use anti parallel vectors, you can never sum it up to 3?

can you?

or my brain isn't working again

1, -1, 1

|z1 + z2 + z3| will be as good as 3|a + b + c| where a,b,c = 1 or -2

*-1

aw

I did something wrong there

anonymous

@YashasSamaga I am saying that z1,z2,z3 could be anti parallel. Not that they can sum up to 3.

Yashas Samaga

AH that 3 isn't there

now it makes sense

|z1 + z2 + z3| will be as good as |a + b + c| where a,b,c = 1 or -1

so you'll never hit 3

anonymous

7:07 PM

Yes. Then?

Range?

Koolman

Can you find the maximum and minimum values of $(z_1-z_2)^2 + (z_3-z_1)^2 + (z_2-z_3)^$

@anonymous

anonymous

@Koolman What are z1 z2 z3? Complex numbers?

Yashas Samaga

that is same as my question

|z1 + z2 +z3||Koolmans equation| = 4

Koolman

Yeah

Yashas Samaga

that is just another form of writing the equilateral triangle constraint

Koolman

7:16 PM

@YashasSamaga ............= 8

Yashas Samaga

AH yea 8

Sir Cumference

Anyone know how to pronounce "philosophiae"?

Yashas Samaga

u get a 1/2 out

anonymous

Complex numbers can't be compared like that. One complex number cannot be said to be bigger or smaller than another complex number in the complex plane. Do you mean maximum and minimum "magnitude" of that term?

If yes, triangle inequality is probably the starting point

Yashas Samaga

he obviously meant the magnitude

in our context

Koolman

7:18 PM

Yes , magnitude

Yashas Samaga

The last time I solved a complex number problem was last month in a mock test

they are usually stupid

anonymous

Consider an unit circle centred at origin. The extrema will occur at symmetry. That is when they will form an equilateral triangle.

Koolman

@anonymous but we have to satisfy other condition given in question

Yashas Samaga

we have already considered it, didn't we?

|sum of z||koolman equation| = 8

it is accounted for ^

Koolman

I think we have to apply it again to find maximum and min

anonymous

7:25 PM

Maximum is 9 (of Koolman's expression) if I did it correctly.

When the sides form an equilateral triangle.

Yashas Samaga

0o

you cannot have an equilateral triangle

u'll get a div by zero

anonymous

@YashasSamaga What? I'm talking about Koolman's expression

Yashas Samaga

you edited ur msg -,-

anonymous

Yep :P

Yashas Samaga

and btw it cannot have a maxima

isn't it obvious?

anonymous

7:27 PM

@YashasSamaga Why?

Yashas Samaga

you can rewrite it sum of sides of the triangle?

you have no limit for the side?

anonymous

(Note that I am talking about Koolman's problem independently)

Yashas Samaga

yea I am talking about that

Koolman

The triangle will lie in a circle of radius = 1 @YashasSamaga

anonymous

Take 1,e^(i2pi/3) and e^(i4pi/3)

You will see that the square of the sides add up to 9

Yashas Samaga

7:29 PM

z1-z2 gives the side of the triangle as a vector

oh wait

I was thinking of |z1 -z2|^2 + |z2-z3|^2 + |z1-z3|^2

-_-

I need to get some sleep

anonymous

Probably :)

See you tomorrow

Bye:)

Yashas Samaga

I am writing 8 as 4

I have got 8 hours of sleep since last 3 days

I spent the whole night yesterday solving some photoelectric problem

anonymous

@YashasSamaga Close your laptop and go to sleep now

Yashas Samaga

0

Q: Calculating saturation current and energy associated with a band of wavelengths

Consider white light whose wavelength spread is from 400nm to 700nm. Its energy is uniformly distributed in this spectrum. The light is incident on metal A of work function 1.55eV. Saturation photocurrent is 6mA. Now the same light is incident on metal B, work function 2.48eV. Calculate the total...