The h Bar

Mohamed Obeidallah

07:41

@PM2Ring I forgot that nuclear explosions don't just produce tremendous heat but also dangerous radiations. So, if say calcium rich objects are in the ground zero of an atomic explosion, the calcium nuclei will get destroyed by the neutrons, gamma radiations, alpha particles, etc. that were produced by the atomic explosion although the temperature isn't enough to destroy calcium nuclei. Correct?

user434058

08:41

@PM2Ring Hey, I saw you're from Australia... So I was wondering that do you listen to Peking Duk?

Loong

10:13

@MohamedObeidallah Let’s see.

You need thermal neutrons for a reaction with Ca-40.

The effective thermal neutron fluence near the hypocentre of Hiroshima was about 1.3E+13 cm^-2.

The effective cross section of Ca-40 for thermal neutrons is about 0.41 b according to the old table of nuclides I just found on my desk.

Thus, the neutron radiation from the Hiroshima bomb might have converted about 5E-10 % of the affected Ca-40 atoms to Ca-41.

Mohamed Obeidallah

11:16

@Loong Thanks, sorry because I'm not that knowledgeable in maths so last statement "Thus, the neutron radiation from the Hiroshima bomb might have converted about 5E-10 % of the affected Ca-40 atoms to Ca-41." translated to Ca-41 will decay after that but what do you mean by 5E-10%? Do you mean only a few of 40Ca destroyed and not many?

Loong

12:04

Yes, only about 0.0000000005 % of the Ca-40 atoms near the hypocentre were converted to Ca-41.

And yes, Ca-41 decays after that; however, it has a half-life of 1.02E+5 years so that the decay is very slow.

Mohamed Obeidallah

@Loong do you know what process that will change (or destroy) any isotopes of calcium regardless if it is stable or not to different states in a very short time other than by silicon burning?

Knight

@skillpatrol Hi

skillpatrol

hi pal

Knight

@skillpatrol What are you arranging for me in your New Year Party?

skillpatrol

rock n' roll

Knight

12:19

@skillpatrol But who was that on phone, who invited me to your house?

@skillpatrol Was he your friend?

skillpatrol

raider nation is brotherhood, pal :-)

Knight

@skillpatrol You know yesterday I was kicked out, no one was there to heal me.

@skillpatrol Will you protect me today?

skullpatrol

yes

Knight

@skullpatrol What are doing right now?

skullpatrol

chillin

Knight

12:27

@Qmechanic Will you please explain me this post of mine

3

Q: An introductory explanation of the electromagnetic radiation equation

In the introductory books we find the equation of electric field, by a point charge, as $$ \mathbf{E} = \frac{q}{4\pi\epsilon_0}~\frac{\hat r}{r^2}$$ In Feynman Lectures on Physics we find some paragraphs like this Maxwell noted that the equations or the laws that had been discovered up ...

electromagnetic-radiation

2

@skillpatrol How old are you? (I know you can't tell your age here, all I want is a rough idea)

skullpatrol

google.com/…

Knight

@skullpatrol save me, save me @ACuriousMind has come. Oh Please save me

anyone around?

skullpatrol

12:44

24 mins ago, by skillpatrol

raider nation is brotherhood, pal :-)

Knight

@skullpatrol are you a great fan of football?

skullpatrol

yup

Knight

@skullpatrol do you live in Germany?

skullpatrol

nope

Knight

ok

@skullpatrol what's your age?

skullpatrol

12:49

can't say, sorry

Knight

@skullpatrol Any rough idea?

skullpatrol

more than a rookie

21 mins ago, by skullpatrol

https://www.google.com/imgres?imgurl=https%3A%2F%2Fstatic.clubs.nfl.com%2Fimage%2Fprivate%2Ft_editorial_landscape_12_desktop%2Fraiders%2Fsujjwtns7ytgzzh6asae&imgrefurl=https%3A%2F%2Fwww.raiders.com%2Fvideo%2Fmore-than-rookies-ep-1-school-s-out&tbnid=YTQSVLaOF43TYM&vet=12ahUKEwiaiuDH7NrmAhWFx54KHSe2BU0QMygQegUIARD0AQ..i&docid=Y_ihOEodr68mcM&w=1280&h=720&q=raider%20nation%20is%20brotherhood&client=firefox-b&ved=2ahUKEwiaiuDH7NrmAhWFx54KHSe2BU0QMygQegUIARD0AQ

rookie

Noun: rookie (plural rookies)

An inexperienced recruit, especially in the police or armed forces.
A novice.
An athlete either new to the sport or to a team or in his first year of professional competition, especially said of baseball, basketball, hockey and American football players.
(Britain) A type of firecracker, used by farmers to scare rooks.
rookie m or f (plural rookies)
rookie...

Adjective: rookie (comparative rookier, superlative rookiest)

non-professional; amateur
The game was going well until I made that rookie mistake.
the rookiest of rookie mistakes

Yuvraj Singh...

No, no no, no no..... Oooo

skullpatrol

13:05

Welcome @Marla :-)

Knight

My age is $ e^{i\pi}$

Marla

@skullpatrol .. . thank you skull. Just visiting from the Electrical Stack.

skullpatrol

coolio

Marla

What's all this "Raiders" stuff? My Denver Broncos play the Raiders today.

Yuvraj Singh...

Hello Marla.

Marla

13:08

Hello Yuvraj

skullpatrol

yup, gonna end our play-off hopes?

Marla

why not. Denvers already out of play offs

spolers :)

skullpatrol

:-)

Yuvraj Singh...

@Marla. Electrical engineer?

Marla

yes. Recently retired now.

Yuvraj Singh...

13:10

Wow! What kind of work?

Marla

First it was high power VHF transmitters. Then later in Induction Heating industry

see profile

Yuvraj Singh...

L, C, R circuit?

Induction heating.

Marla

Yes, induction heaters use a resonant circuit .

that was high power too. Up to 1000 kW.

Yuvraj Singh...

Actually during our high school days our teacher use to say RC circuit won, t exist in real?

L

Due to its power loss.

Marla

I don't quite understand what you are saying

Yuvraj Singh...

13:17

Actually I was referring to my teacher words, he said RC circuit is not practically efficient.

Marla

well, teachers say many things :)

Yuvraj Singh...

Do we use RC circuits in some electrical equipment?

Marla

yes. All the time. Filters is one area.

ACuriousMind

Hmm, two upvotes on an answer that's almost five years old, no other activity on the question either. I wish there was a way to see when a question gets linked by another. @EmilioPisanty I don't think that's something the SEDE data shows, is it?

Marla

and spurious (not desired) R and C exist everywhere.

Yuvraj Singh...

13:20

LC circuit too?

Marla

yes. A capacitor has an internal resistance as does L.

In induction heating, C is used to cancel out L.

Yuvraj Singh...

Hmm.. My teacher is....

Marla

also C is used to cancel out L in AC motors.

Yuvraj Singh...

Cancel out?

Marla

cancel out reactive power (as opposed to real power)

so electrical generator only has to supply real power.

Yuvraj Singh...

13:23

OK I have a question when I say 10 units power what does it mean?

In electricity.

Marla

power is usually measured in watts. Could be milli-watts. Depends on what units.

skullpatrol

@ACuriousMind perhaps the question got some exposure on the side bar

ACuriousMind

Sure, that's also possible

Yuvraj Singh...

I remember one of my old high school question which I didn, t get till now can I ask?

skullpatrol

> Don't ask about asking, just ask.

or

askaway

:-)

Yuvraj Singh...

13:28

Actually a common confusion like I had 15 fans, and 20 heater use the total power 50W they use

So power use by each 15 fan is equal.

@Marla

Marla

That is unknown. You could have 15 different fans.

Yuvraj Singh...

15 identical.

Then

Marla

In the same environment, yes they would draw same current. But imagine lining up the fans with one fan pushing the air for the next fan. Do you think the first and last fan would use same amount of power ?

Different load for each subsequent fan.

A motor driven fan uses power according to the load on the motor.

Yuvraj Singh...

Mean resistance. An identical fans having same resistance, are. Connected in parallel, across se voltage should use same power.

Marla

Well, I must go. Thanks for the warm welcome here.

3

Yuvraj Singh...

13:36

Last one, @Marla

skullpatrol

cya

Abhas Kumar Sinha

15:34

@Knight bad joke or bad maths, that equals -1

@skullpatrol yo pal

Knight

@AbhasKumarSinha Is it equal to -1? I didn't know that

Abhas Kumar Sinha

@EmilioPisanty good morning sir, I've a question, about spin of the nucleus. Why I can't imagine it as the equal to classical system?

Knight

He is not here

Abhas Kumar Sinha

@Knight Range of real part is $[1, -1]$ and same for imaginary part.

@Knight Ik

@Knight and @FakeMod came same time with same profile pic color!! Fishy! XD

klol

Knight

@AbhasKumarSinha Can you tell who is knight and who fakemod just from profile picture in right corner?

Abhas Kumar Sinha

15:38

@Knight no

@Knight violet one is fakemod

Knight

@AbhasKumarSinha Yesterday you got me kicked out

user434058

Now I am not gonna say that we(@Knight and @FakeMod) are the same accounts because I fear ACM's wrath ;)

Abhas Kumar Sinha

@Knight klol, who cares, don't take your life very seriously, you won't get alive out of it.! :)

Knight

@FakeMod is Knight

Abhas Kumar Sinha

@Knight @FakeMod delete messages asap

klol

Knight

15:40

@AbhasKumarSinha Fakemod is knight and knight is novalium company and and novlaium company is skullpatrol

user434058

No I want to mess everything up.... I AM GROOT!!!!

Abhas Kumar Sinha

@FakeMod yo yo yo, my boi! :)

@Knight I'm me

Knight

@FakeMod What is Groot?

@AbhasKumarSinha is Yuvraj Singh

user434058

@Knight That escalated quickly!!

Abhas Kumar Sinha

@Knight We are Groot

Knight

15:42

@AbhasKumarSinha @FakeMod I'm Sir Facearea

Abhas Kumar Sinha

@Knight I'm leonardo da vinci

Knight

@FakeMod is Facebook

@knight is Dark Knight

Abhas Kumar Sinha

@Knight Yes Mark Zuck

@Knight Abhas is Abhas

Knight

@AbhasKumarSinha Who are you , my mind is very curious

Abhas Kumar Sinha

@Knight @ACuriousMind ^

lol

XD

Knight

15:43

JMac is Jack Ma?

Abhas Kumar Sinha

@Knight yea

Knight

@FakeMod Where are you pal?

Abhas Kumar Sinha

@Knight coming

Knight

@AbhasKumarSinha Are you going to washroom?

Abhas Kumar Sinha

@Knight Dinner

@Knight no not at washroom but at dining room

Knight

15:46

@AbhasKumarSinha Oh I see it's knight over there

Abhas Kumar Sinha

Will join after DAT

@Knight Okay, will join you then

Knight

@AbhasKumarSinha Have a great dinner

Abhas Kumar Sinha

@Knight let's see

Knight

@FakeMod Are a university student?

@user8718165 Are you me?

user8718165

@Knight Nah ;-) How are you guys?

Abhas Kumar Sinha

16:09

yo yo yo yo yo

Yo, killing it with the guillotine flow
Career got legs like a millipede, bro
I bring truth with the bitterness
Since I was a sonogram, I've been kickin' it
I'm never nice, I say things impolitely
So, let me get under your skins like IV

With just the vernacular, axed and I quelled
Everybody who said that rap wouldn't sell
They laughed at my folks and my home
The ones that cracked up hysterically over my clothes
Approach me now while I'm laughing my way
To the bank knowing they can't afford me no more

@Knight yo yo yo

@Kyubey yo bro :) Sup?

Kyubey

16:23

@AbhasKumarSinha I'm fine and you?

Abhas Kumar Sinha

@Kyubey Great, what are you doing?

Knight

@AbhasKumarSinha Why you always write while court’s verdict here? Here you should write short messages

Kyubey

@AbhasKumarSinha Just finished watching the monster anime

Abhas Kumar Sinha

@Knight klol, I thought I'd fight for you becauz you were kicked again.

@Kyubey Naruto? You've completed that one?

Yuvraj Singh...

Two days to go!

Knight

16:25

@AbhasKumarSinha Your last words are very hard to understand? Was I kicked out when I was offline?

Yuvraj Singh...

Tik tok Tik tok........

Kyubey

@AbhasKumarSinha no! Not now. I would watch it sometimes later.

Knight

@YuvrajSingh... Who are you in real life?

Abhas Kumar Sinha

@Knight If you get kicked, then I'll diss kicker with my rappin skills.

@Kyubey You live in Japan?

Knight

@AbhasKumarSinha You are my real brother

Kyubey

16:26

@AbhasKumarSinha no i'm from India.

Knight

Guys please careful be very careful Mr.ACM is here

Yuvraj Singh...

@Knight man with two legs, two hands, two eyes, and one brain and one heart!

Abhas Kumar Sinha

@Knight yes bro yes. Make corrections to the diss rap if you think you can improve it.

Knight

@YuvrajSingh... Who’s holding that one heart ?

Abhas Kumar Sinha

@Kyubey pata tha

Yuvraj Singh...

16:28

@Knight God!

Abhas Kumar Sinha

@Knight his bro, me @YuvrajSingh... ;)

Knight

@AbhasKumarSinha What you ate in dinner?

Kyubey

@AbhasKumarSinha and it's quite obvious from your name too! (Though not from mine).

Yuvraj Singh...

@Knight kidding! What you want to know about me?

Knight

@YuvrajSingh... Is your real name Abhas Kumar Sinha?

Yuvraj Singh...

16:29

@Kyubey is that a pokémon

@Knight??????????

@AbhasKumarSinha he is kidding with you.

Kyubey

@YuvrajSingh... No not at all! I think no one here might be able to guess it. Its from a dark themed anime.

Knight

@YuvrajSingh... is Abhas and @AbhasKumarSinha is Yuvraj, right?

Yuvraj Singh...

@Knight No!

Knight

I’m not enjoying today, I’m leaving

Yuvraj Singh...

@Knight come on! It was a joke!

@AbhasKumarSinha what, s plan for new year?

Abhas Kumar Sinha

16:45

@YuvrajSingh... hello, I was eating, nothing much, I just get 8 packs before march.

;)

@Knight yo yo yo yo yo!

@YuvrajSingh... hello, I was eating, nothing much, I just get 8 packs before march.

Theorem: Nothing is bigger than infinity.
Proof: 1,2,3...infinity...nothing

Semiclassical

but nothing + 1 is 1, hmmmmmm

Abhas Kumar Sinha

@Semiclassical don't go in details, that's how math works.

Semiclassical

smile and nod, got it

Abhas Kumar Sinha

@Semiclassical prove it

@Semiclassical rename your kid mathematics to become father of mathematics

Semiclassical

lol

Abhas Kumar Sinha

16:58

@Semiclassical hehehe XD :)

Kyubey

@AbhasKumarSinha you in college?

Knight

17:24

@Semiclassical Are you somewhere between quantum and classical mechanics?

Semiclassical

that is the allusion, yes

Knight

@Semiclassical Wow

@Semiclassical please help me on this post

3

Q: An introductory explanation of the electromagnetic radiation equation

In the introductory books we find the equation of electric field, by a point charge, as $$ \mathbf{E} = \frac{q}{4\pi\epsilon_0}~\frac{\hat r}{r^2}$$ In Feynman Lectures on Physics we find some paragraphs like this Maxwell noted that the equations or the laws that had been discovered up ...

electromagnetic-radiation

@dmckee can you teach me the second law of thermodynamics through conversation over here?

Semiclassical

pass

Knight

@Semiclassical what?

Semiclassical

I'm not interested. If you don't like Feynman's presentation, find a presentation you do like

Knight

17:28

@Semiclassical why you are not interested?

@Semiclassical What about second law of thermodynamics?

Semiclassical

still not interested, and I'm not obliged to justify myself beyond that.

Knight

@Semiclassical Are you interested in normal conversation?

Semiclassical

if I was, I'd be talking.

Knight

@Semiclassical So, basically you mean that you are not liking me pinging you? Ha?

Semiclassical

I'm saying that, if I'm interested pursuing a topic, I'll engage with it myself. Spamming random people on chat about topics is a good way to get entirely ignored.

Knight

17:34

@Semiclassical okay. I just thought I could establish a good conversation with you. No matter, there are many other people who wouldn’t ignore me for nothing.

@user8718165 Are you me?

user8718165

@Knight nah. I told you before ;)

Knight

@user8718165 Am I You?

@dmckee Are you here?

user8718165

@Knight Still... I don't think so. How are you doing BTW?

Kyubey

@Knight what's this "are you me thing?"! Sorry, I didn't get the joke.

Knight

@Kyubey You better ask ACM about it

@user8718165 I’m good, how are you?

user8718165

17:38

@Knight I'm hardly awake now with my eyes red :(

Knight

@user8718165 Why? Are you sick?

ACuriousMind

@Knight Stop annoying other users.

3

user8718165

@Knight nope. Tired... :-)

A few days left... and 2019 will also be over. I learnt a lot of this this year. Yeah :-)

Knight

@ACuriousMind What I did this time?

@user8718165 2019 is about to over and so the good things

@ACuriousMind Please reply, what I did this time?

ACuriousMind

@Knight Pinging random users with inane questions like "Am I you?" is not a proper usage of pings. Cf. our chat guidelines: "Don't ping random users. You may use pings, but responsibly and sparingly. Err on the side of not pinging when you're unsure that the pingee(s) would be interested in your message(s)."

Knight

17:44

@ACuriousMind Are you alluding to semiclassical?

ACuriousMind

And just there, you pinged me twice with the same message within less than a minute.

Knight

What I pinged you?

ACuriousMind

"Pinging" refers to addressing other users via @.

user8718165

@Knight Yeah. That's sad. I'm sorry but I'm too tired to chat now. I've a bit of orgo to finish too. See you later :-)

Knight

@user8718165 Bye

ACuriousMind

17:46

@user8718165 I'm sure there are plenty of things left to learn next year ;)

Knight

@ACuriousMind I know that you are trying to keep this chat room as intellectual as possible, so I will not spam it with too much jokes. I will converse on healthy topics only.

user8718165

@ACuriousMind Hello. Hope you guys will be around so that I can talk with you next year.

ACuriousMind

That's...not what I'm trying here, really. I just don't want anyone who enters this room to get pinged with nonsense they didn't ask for.

Knight

Can someone tell me what is :)

ACuriousMind

@user8718165 I don't plan on going anywhere, at least :P

Kyubey

17:49

@Knight It's a smile

Knight

@ACuriousMind Yeah, I know that’s kinda thing that will discourage users from entering this room, am I right?

@Kyubey you want some fun?

ACuriousMind

@Knight Yes, indeed.

Kyubey

@Knight sure!

Knight

@ACuriousMind So, from now on I will joke with people who consents it, okay

@Kyubey You know who am I?

user8718165

@ACuriousMind Yeah. It's a very good news (at least for me), and a belated Merry Christmas to you😊

Kyubey

17:52

@Knight I know you. You are me!

Knight

@Kyubey Yes, and I am you and you are Abhas and Abhas is Yuvaraj

Yuvraj is Novalium and Novalium is Skull

Kyubey

@Knight the other ones were not obvious but still we do have a 'k' in our names na!

Knight

@Kyubey Yes, so we are basically talking to ourselves, ha?

user8718165

@Knight @ACuriousMind Good Bye (for now) :-) See you later.

Knight

@Kyubey As you an Indian, therefore Good Knight

Kyubey

17:56

@Knight Ah! Yes I (we) am (are)!

Knight

@Kyubey Good Knight to Knight (Kyubey)

Kyubey

@Knight good knight to kyubey (knight)!

Mohamed Obeidallah

@Loong do you know what process that will change (or destroy) any isotopes of calcium regardless if it is stable or not to different states in a very short time other than by silicon burning?

Loong

You have already asked me that question.

user434058

18:17

@Knight I had to go... And no I am a 16 year old high school student.

user434058

@Knight Seems like you are under an identity crisis!! Go meet a psychiatrist who might help you discover your true self!! :P

Physics Meta

19:18

0

Q: Stop killing suggested edits in the name of "conflicted with a subsequent edit"

I saw this and thought to edit it by adding a blockquote, do some MathJax formatting and editing tags. And so I devoted 7 minutes (on a mobile device), trying to make StackExchange a better place. And just when I submitted my edit, suddenly out of nowhere, @BenCrowell just did this edit (yeah I k...

discussion feature-request editing suggested-edits

Transcript for