Why is the electric field between two conducting parallel plates not double what it actually is?
Field between the plates of a parallel plate capacitor using Gauss's Law
How do I read / convert an InputStream into a String in Java? If you have a java.io.InputStream object, how should you process that object and produce a String?    Suppose I have an InputStream that contains text data, and I want to convert it to a String, so for example I can write that to a log file.  What is the easiest way to take the InputStream and convert it to a String?  public String convertStreamToString(InputStream is) {     // ??? } We know that Accio spell (aka ) has some limits:   It can be blocked (e.g. Harry couldn't Accio the Diadem in RoR in Deathly Hallows). Many more failures are listed on Wikia.   But what are the exact full rules and limitations governing the spell in Harry Potter world?   Distance?  Line-of-sight?  Knowing exact or approximate location?  Specificity of item (e.g. "Accio Broom" seemed to work for Weasleys in OotP to bring their locked-up brooms - why not just a random broom?) Types of Accio-able stuff? Can you Accio water? Lump of earth? Gases/liquids/etc...? Can you Accio based on jQuery selector (or an SQL where clause), for lack of a better description? E.g. "Accio the book that has the word 'Flammel'"? "Accio biggest green ball from this room"? Can you Accio ALL items of a kind? (the reason I thought of this whole question was seeing "Accio all guns" comment in ). Can you Accio vague stuff? ("Accio meal"). Other rules that can be inferred.   NOTE: While Wikia article has some of the info, it is clearly very lacking in details on specific rules based on specific instances in canon. I'm looking for a fully comprehensive, organized ruleset for the charm, not merely 1-2 tidbits in Wikia article. I'm loading elements via AJAX. Some of them are only visible if you scroll down the page. Is there any way I can know if an element is now in the visible part of the page? How to fix "The system is running in low-graphics mode" error? Note: This is an attempt to create a canonical question that covers all instances of &quot;low-graphics mode&quot; error that occurs to a user, including but not limited to installation of wrong drivers, incorrect or invalid lightdm greeters, low disk space, incorrect installation of graphics card like ATI and Nvidia, incorrect configuration of xorg.conf file while setting up multiple monitors among others. If you are experiencing the &quot;low-graphics mode&quot; error when trying to login but none of the following answers work for you, please do ask a new question and then update the answers of this canonical question as and when your new question gets answered.   When I try to boot into my computer, I am getting this error:  The system is running in low-graphics mode Your screen, graphics cards, and input device settings could not be detected correctly. You will need to configure these yourself.   How do I fix the failsafe X mode and login into my computer?  Answer index: Can we have a way to edit bounty custom message? writing js objects to files (including methods) in nodejs? QtCreator and Command Line Arguments Let $T(n,x)$ be the nth Chebyshev polynomial of the first kind and let $U(n-1,x)$ the $(n-1)$th Chebyshev polynomial of the second kind. Would any one kindly help show that   1) $n$ is prime iff $T(n,x)$ is irreducible in $\mathbb{Z}[x]$.  2) $n$ is prime iff $U(n-1,x)$, expressed in powers of $(x^2-1)$, is irreducible in $\mathbb{Z}[x]$.   Many Thanks!!    No "ordering" is implied here. The wording of the question was done in similar fashion  as any question in any math/research question. I do not see how a person who is asking for help would be ordering people to help.   Any way back to the topic,  For the first part of the question, I noticed that if n is prime, then T(n,x) satisfies  Eisenstein's Irreducibility Criterion. But I am not sure how to show if T(n,x) is irreducible then n is prime. In a moment of cheapness, I decided not to order a 5v to 3.3v level shifter from Sparkfun, but instead to put it together myself.  The  used a  MOSFET, but since I enjoy surface-mount soldering about as much as root canal treatment, I decided to use a  that is through-hole mounted and easily available from my preferred supplier.  The results of this were sub-optimal.  When pulling the 5v line to ground, all was fine - the 3.3v side went to 0.07v.  But when pulling the 3.3v to ground, the 5v line showed around 4.14v (it was otherwise a touch above 5.1v).  On a closer reading of the datasheets involved, as well as the original Philips application note on the subject, I began to come to the conclusion that the gate threshold voltage was the problem.  By altering the schematic and tying the MOSFET's gate to 5v instead of 3.3v, both sides seem to work fine.  Pulling either side low causes the other side to go low.  I'm not, however, at all confident that this is actually a sane thing to do.  My understanding of the original schematic isn't deep enough to form a sensible opinion.  Will this modified schematic work, or are the current good results I'm seeing mere fluke or a precursor to something releasing magic smoke? Why does unlocking the bootloader wipe phone? Modify footer used by elsarticle.cls Let's assume that one has some modern HP printer and/or scanner which is not supported by HPLIP package from official repository. Currently Ubuntu versions have :  trusty (14.04LTS): 3.14.3-0ubuntu3.4 xenial (16.04LTS): 3.16.3+repack0-1 bionic (18.04LTS): 3.17.10+repack0-5 focal (20.04LTS): 3.20.3+dfsg0-2 groovy (20.10): 3.20.5+dfsg0-3build1 hirsute (21.04): 3.21.2+dfsg1-2   What can one do if printer is supported in newer version of HPLIP (checked this in )? MLE for Uniform $(0,\theta)$ I am a bit confused about the derivation of MLE of Uniform$(0,\theta)$.  I understand that $L(\theta)={\theta}^{-n}$ is a decreasing function and to find the MLE we want to maximize the likelihood function.  What is confusing me is that if a function is decreasing, then wouldn't the function be maximized at the smallest input rather than the largest?  Thank you in advance for your help. How do I make animations a steady speed? How to get div height to auto-adjust to background size? How do I get a div to automatically adjust to the size of the background I set for it without setting a specific height (or min-height) for it? GTA 5 Social club I used to play gta 5 online on my ps3 but it ended up breaking and I can't use it anymore I purchased the game for xbox 360 and started playing the game all over again and some of you know how hard that can be specially online.. So I was wondering if I could somehow transfer my old ps3 social club account to my xbox an use it on xbox from now on? How to assign from a function which returns more than one value? When Frodo put on the One Ring, both the Nazgul and Sauron himself found Frodo. However when Bilbo had the ring and possibly used it many times, Sauron sought Gollum to get a hint on where to look for the ring and send the Nazgul after it.   Sauron sought Gollum before Bilbo wore the ring at his birthday party, slightly after that time, he was very effective at locating Frodo when Frodo put on the ring. So I guess it's not a matter of Sauron gaining any extra powers with time.  Also Bilbo seemed to use the ring without it bothering him at any point, unlike Frodo who seemed to be very troubled when using the ring. How is that possible? How do I get the local machine name? Why do clocks measure arc-length?