The h Bar - 2018-09-17

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Anonymous

12:02 AM

Hmm. And what value of cut in voltage did you get?

Anonymous

I'd probably re-do the experiment with another diode

Andrii Kozytskyi

yeah I was about to blame it on a defect diode

the cut in voltage was also 0.2

as opposed to what should be 0.3 for germanium

2 hours later…

2:32 AM

Replicating the double-slit experiment with antimatter / Lea, Medium

2:43 AM

hey

user image

any idea what change of the charge separation is supposed to mean?

Anonymous

@AndrewGazelka Crude guess: rate of change of separation between plates of the charges capacitor?

Anonymous

They're probably asking you to find out how the current changes as you change the distance between the two plates.

user image

I'm not sure

maybe they are talking about rate of change of just current?

although that is a very overcomplicated way to state it

Anonymous

2:59 AM

@AndrewGazelka In question (3), they mentioned the word "separation"

Anonymous

So I'd guess it has something to do with the separation between the plates

I guess I'll just assume that

Anonymous

And you won't be able to solve (5) till you solve (1)-(4) I suppose

Anonymous

Anyway, I do concur that the language is a tad ambiguous

Anonymous

Maybe verify it with your professor or whoever gave you the question

3:05 AM

user image

I mean that is 4

I just don't see your interpretation of #3 being relevant to #5

I might be wrong though

2 hours later…

danielunderwood

4:42 AM

So I'm going through Zwiebach and he says that due to the Lorentz force law, we look for an action that works for the four-velocity and the obvious choice is $\int A_\mu dx^\mu$. Is it reasonable to try to look for a field $B_{\mu \nu}$ that results in an action $\int B_{\mu \nu} dx^\mu dx^\nu$?

danielunderwood

5:14 AM

Hmmm it seems I'm stuck on getting equations of motion out of that action. I can't easily do integration by parts to make everything nice

Actually that action doesn't even make sense for a particle since you have two intervals. You'd be tracing out a surface in spacetime

6:06 AM

0

Q: Upper Troposphere temperature with 1K increase of surface temperature

I have a question about my Physics Stack Exchange post: Estimate the change in temperature in upper troposphere when there is a 1K surface temperature increase I was directed here to ask a homework question. Linked to original question. Please, any help!

2 hours later…

8:00 AM

I've removed some messages that would live better in private.

Captain Bohemian

8:30 AM

I find it's not easy to surf internet on mobile phone--the screen is too small to accommodate the whole webpage and it may not be easy to type because I may mistype due to my bigger fingers than the screen keyboard.

so I don't understand why some people have mobile phone rather then computer to surf internet.

and as I checked the prices of smartphones in shops, they are so expensive, more expensive than some computers.

Anonymous

@CaptainBohemian A PC is not very portable

Anonymous

I find it easier to text on mobile. Also, you get notifications even when you are in the shower (i.e. you don't always need to sit in front of the screen)

Captain Bohemian

@Blue but there are very thin and light notebook computers, too.

Anonymous

@CaptainBohemian Sure. But I wouldn't carry those in the shower ;)

Anonymous

Nor when I'm in the car

Captain Bohemian

8:40 AM

@Blue I find it's very awkward to text on mobile phone; I prefer to text on messenger.

I have not texted on mobile phone for long.

Anonymous

Well, for quick messages I find using the mobile phone more efficient

Anonymous

Too lazy to open the PC everytime

Anonymous

Whether the perpetual contact with the virtual world is a good thing or not...that's another debate tho.

Captain Bohemian

also free wi-fi is not stable and may break anytime in the middle of your checking research.

Anonymous

I use mobile data when I'm travelling. It's very cheap here (and stable too)

Captain Bohemian

8:47 AM

I only think of to toch virtual world when my real world lack people.

that's why I find forums on web.

@Blue come on, why do you want to access to a computer in the short interval of shower?

Anonymous

Fear of missing out

Fear of missing out, or FOMO, is "a pervasive apprehension that others might be having rewarding experiences from which one is absent". This social anxiety is characterized by "a desire to stay continually connected with what others are doing". FOMO is also defined as a fear of regret, which may lead to a compulsive concern that one might miss an opportunity for social interaction, a novel experience, a profitable investment, or other satisfying events. In other words, FOMO perpetuates the fear of having made the wrong decision on how to spend time since "you can imagine how things could be different...

Anonymous

Okay, the shower thing was more of a joke :P

Anonymous

But yeah, it's useful when you're travelling

Anonymous

I can't carry a laptop when I'm walking on the road to uni

Anonymous

And if I don't have access to the internet I might miss out on important messages

Anonymous

8:58 AM

All our notices are declared online these days

Anonymous

You might argue that it is an addiction. I do agree, but well, it hasn't harmed me in any substantial way, yet. So I'll let it be

Captain Bohemian

I didn't have a mobile phone before I graduated and my department office thought I cheated them that I had no mobile phone.

Anonymous

"cheated"?

Captain Bohemian

deceived

Anonymous

But why would they think so?

Captain Bohemian

9:02 AM

because all of my classmates had mobile phone.

The department office asked my mobile phone number for the convenience of contacting me, but I told them I had no mobile phone, then they tought I had one but didn't want to give them the number.

Anonymous

Lol

Anonymous

I see

Captain Bohemian

I was really too poor to buy a mobile phone.

Anonymous

One of my best friends in high school was exactly like you. He opposed the use of mobile phones at a philosophical level :P

Captain Bohemian

I always used messenger to contact classmates back then.

Anonymous

9:05 AM

@CaptainBohemian My first mobile phone was a second hand one. Never really got an expensive one till I got into college

Captain Bohemian

but it's strange that administartors don't tend to use messenger.

Anonymous

The first one was pretty cheap. Like Rs. 2000

Anonymous

$\approx$ 27$

Anonymous

(A Chinese model iirc)

I still don't have an expensive phone. The most expensive phone I ever bought is my current one, which is a OnePlus 3. It was about £300.

Captain Bohemian

9:06 AM

I actually have never bought a mobile phone. I always used what others gave me.

and the first time I had strong motivation to get a mobile phone was the afraid of missing recruiters' notice after graduation.

The new iPhone costs more than a kidney

$1000

Anonymous

That's......a scary comparison :P

@AvnishKabaj the top end phones are effectively jewellery. They are bought for status not functionality.

3

@JohnRennie spot on

(unlike kidneys :-)

2

9:10 AM

:P

The top selling premium phone in India is the OnePlus 6. That is half the price of an iPhone and it's an awesomely good phone.

@JohnRennie yup yup

Maybe I'll get that next year

If I get into a good college

Anonymous

On the other hand, there's Samsung with their 9th version of the Galaxy model. No idea how long they'll stretch it!

Anonymous

They sure need to change their naming schemes, lol

Captain Bohemian

I don't think I need a phone besides for recruiters' notice and occasional situation. I only need internet outside school where I have never got any real friend.

2 hours later…

11:28 AM

@AvnishKabaj I'm sure many surgeons would be interested to know where you can procure kidneys for only $1000 ;P

Anonymous

Certainly, not a thing to be proud of, but if you visit one of the rural areas here, there are many who would be willing to sell one kidney for $1000, to feed their family or treat them.

Anonymous

$1000 is more than the annual salary of many people here

@Blue Ah, that's just what you'd pay the donor, though, not the total cost of the kidney (which would include operation cost, transportation, etc.)

Anonymous

Transportation, well, if the donor is willing to travel to the hospital where the operation is being performed....that would be cut down

Anonymous

And $1000 is a lot. Several would even agree for $500

Anonymous

11:43 AM

But yeah, if we are gonna take the average rates for kidney transplants...it's gonna be like Rs. 3 lakhs $\approx $ 4000$

Anonymous

And higher in the more elite hospitals

Anonymous

Half of the cost depends on the hospital and the surgeons I guess

is your dad a surgeon?

Anonymous

@user2646 Nope

the iOS updates are ridiculous

oh yeah it was Sid

who i haven't seen around in awhile

12:34 PM

@ACuriousMind I don't want to go to jail shhhhhh....

:P

Captain Bohemian

12:48 PM

I indeed spend most of my time on internet now but I think that's because my reality has nothing, not because of addiction.

2 hours later…

3:17 PM

Busy Doing Nothing (Christopher Robin Soundtrack)

6 hours later…

8:52 PM

hmmm

2 hours later…

danielunderwood

10:52 PM

I suppose everyone must be on vacation today

Captain Bohemian

It's sunrise, and I have felt sleepy.

11:15 PM

uhhhh

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