Let us consider two plane waves of same amplitude and frequency but having 180 degrees phase difference.Both the waves are having energy E in them which is directly proportional to the square of the amplitude.So the total energy is two times E.Now if both waves interfere,the amplitude of resulting wave is zero and the energy in the resulting wave is zero.What happend to the energy in both plane waves
What happens to the energy when waves perfectly cancel each other (destructive interference)? It appears that the energy "disappear" but the law of conservation of energy states that it can't be destructed. My guess is that the kinetic energy is transformed into potential energy. Or maybe it depends on the context of the waves where do the energy goes? Can someone elaborate on that or correct me if I'm wrong?
Make all i.stack.imgur.com links protocol-relative Stack Overflow has HTTPS in some places! However, this breaks most existing image links. Could those be made protocol-relative, or react to the requesting protocol, or just always use HTTPS?  The same applies to .sponsor-tag-img. Microsoft.ACE.OLEDB.12.0 provider is not registered I have a Visual Studio 2008 solution with two projects (a Word-Template project and a VB.Net console application for testing).  Both projects reference a database project which opens a connection to an MS-Access 2007 database file and have references to System.Data.OleDb.  In the database project I have a function which retrieves a data table as follows   private class AdminDatabase    ' stores the connection string which is set in the New() method    dim strAdminConnection as string     public sub New()    ...    adminName = dlgopen.FileName    conAdminDB = New OleDbConnection    conAdminDB.ConnectionString = "Data Source='" + adminName + "';" + _        "Provider=Microsoft.ACE.OLEDB.12.0"     ' store the connection string in strAdminConnection    strAdminConnection = conAdminDB.ConnectionString.ToString()    My.Settings.SetUserOverride("AdminConnectionString", strAdminConnection)    ...    End Sub     ' retrieves data from the database    Public Function getDataTable(ByVal sqlStatement As String) As DataTable         Dim ds As New DataSet         Dim dt As New DataTable         Dim da As New OleDbDataAdapter         Dim localCon As New OleDbConnection           localCon.ConnectionString = strAdminConnection          Using localCon             Dim command As OleDbCommand = localCon.CreateCommand()             command.CommandText = sqlStatement             localCon.Open()             da.SelectCommand = command             da.Fill(dt)             getDataTable = dt         End Using      End Function End Class   When I call this function from my Word 2007 Template project everything works fine; no errors. But when I run it from the console application it throws the following exception     ex = {"The 'Microsoft.ACE.OLEDB.12.0'   provider is not registered on the   local machine."}   Both projects have the same reference and the console application did work when I first wrote it (a while ago) but now it has stopped work.  I must be missing something but I don't know what.  Any ideas? Page number in title page I want to add page number from 531 to 536 in my latex IEEE conference template. But page number appearing from page 2 i.e. 532.  \documentclass[conference]{IEEEtran} %\IEEEoverridecommandlockouts  \makeatletter \let\old@ps@headings\ps@headings \let\old@ps@IEEEtitlepagestyle\ps@IEEEtitlepagestyle \def\confheader#1{%     % for all pages except the first     \def\ps@headings{%         \old@ps@headings%         \def\@oddhead{\strut\hfill#1\hfill\strut}%         \def\@evenhead{\strut\hfill#1\hfill\strut}%     }%     % for the first page     \def\ps@IEEEtitlepagestyle{%         \old@ps@IEEEtitlepagestyle%         \def\@oddhead{\strut\hfill#1\hfill\strut}%         \def\@evenhead{\strut\hfill#1\hfill\strut}%     }%     \ps@headings% } \makeatother  \confheader{ 2020 IEEE International Conference on Computation, Automation and Knowledge Management (ICCAKM) }   %%footer %\usepackage[pscoord]{eso-pic} %\newcommand{\placetextbox}[3]{ %   \setbox0=\hbox{#3} %   \AddToShipoutPictureFG*{ \put(\LenToUnit{#1\paperwidth},\LenToUnit{#2\paperheight}){\vtop{{\null}\makebox[0pt][c]{#3}}} %   } %} %\placetextbox{.23}{0.055}{\small{978-1-5386-8007-0/19/\$31.00~\copyright 2019 IEEE}}     \usepackage{cite} \usepackage{amsmath,amssymb,amsfonts} \usepackage{algorithmic} \usepackage{graphicx} \usepackage{textcomp} \usepackage{xcolor} \usepackage{float} \usepackage[export]{adjustbox} \usepackage{subcaption}     % %\usepackage[pscoord]{eso-pic} %\newcommand{\placetextbox}[3]{ %   \setbox0=\hbox{#3} %   \AddToShipoutPictureFG{ \put(\LenToUnit{#1\paperwidth},\LenToUnit{#2\paperheight}){\vtop{{\null}\makebox[0pt][c]{#3}}} %   } %} %\placetextbox{.2}{0.055}{978-1-4799-5522-0/15/\$31.00~\copyright 2015 IEEE}   \IEEEoverridecommandlockouts \IEEEpubid{\makebox[\columnwidth]{978-1-7281-0666-3/20/\$31.00~\copyright~2020         IEEE \hfill} \hspace{\columnsep}\makebox[\columnwidth]{ }}      \thispagestyle{plain}     \pagestyle{plain}     \setcounter{page}{531}   \begin{document}  \title{Performance Analysis of Physically     Unclonable Function Based on Voltage Divider Arrays} \author{\IEEEauthorblockN{Sumit Chaudhary$^{1}$}     \IEEEauthorblockA{\textit{Dept. of Electronics and Communication} \\         \textit{MNIT Jaipur, India}\\         2016pev5165@mnit.ac.in}     \and     \IEEEauthorblockN{Chitrakant Sahu$^{2}$}     \IEEEauthorblockA{\textit{Dept. of Electronics and Communication} \\         \textit{MNIT Jaipur, India}\\         chitrakant.ece@mnit.ac.in}}  \maketitle   \end{document} Alice and Bob play the following game with an $n \times n$ matrix, where $n$ is odd. Alice fills in one of the entries of the matrix with a real number, then Bob, then Alice and so forth until the entire matrix is filled. At the end, the determinant of the matrix is taken. If it is nonzero, Alice wins; if it is zero, Bob wins. Determine who wins playing perfect strategy each time.    When $n$ is even it's easy to see why Bob wins every time. and for $n$ equal to $3$ I have brute-forced it. Bob wins. But for $n = 5$ and above I can't see who will win on perfect strategy each time. Any clever approaches to solving this problem? Privacy leak in permalink? Update (Jan 8, 2019) This is now 8 years old, but still getting occasional upvotes/attention, so I thought it's worth giving a summary of the current state.  Despite originally being , over the last decade some changes have made the privacy implications much clearer.  You now click &quot;share&quot; instead of &quot;link&quot;, and the pop-up is very explicit that the link includes your user ID. There is a  asking that this user ID be anonymized or hashed, to allow users to earn publicity badges (the intention behind having the user ID present in the URL, as per ) while eliminating the privacy issue. Original Post It seems to me there is something of a privacy leak when permalinking to a question.  For what I would assume is the purposes of tracking which user is responsible for bringing traffic back to an SE site (for badges, etc.), the user ID of the user obtaining the permanent link . I wouldn't argue that this shouldn't be the case, but I find no warning or mention of this when I do these actions.  I'm sure I'm not the only one that doesn't desire anonymity on SO but would like at least pseudonymity on some places I might share a SO link, such as on a random blog.  As a user, I would not expect sharing a permanent link to leak my identity.   Unless you are familiar with Stack Exchange links or your own userID, it's certainly not obvious by looking at the link that it includes your personal info.  It'd be nice to have fair warning that using that feature will do so, and perhaps provide/describe the workaround: to simply remove the user-id segment from the URL.  Other features would be a preference that formats future permanent links to exclude the user id. Example (from this question)  Permalink:  Link to my user page: Ubuntu 11.10 is installed, and I have updated my system via Ubuntu Software Centre, and after the update 3 updates remain in the list. But I am unable to select them, the tickboxes cannot be checked and Ubuntu Software Centre gives no error when I try to check.  Also, below it says "There is no update to be installed" and even though there seems to be updates Install Updates button is unclickable.  What should I do in order to install these updates? How were the number of rounds for different key sizes of AES selected? The number of AES rounds increases with the key length. Why increase the number of rounds at all, and how were these round counts chosen? Is it possible to prove that $1+1 = 2$? Or rather, how would one prove this algebraically or mathematically? I just updated my iMac to Mojave, and am still trying to setup my preferences.  I tried dark mode, but did not like it (half of me apps seem to ignore it anyway).  I switched to light mode, but this too has problems. The File Save dialog shows a list of Directories and existing files, but the latter are very light grey, almost indistinguishable from the background.    I have searched the Preferences menu, but can't seem to find any setting to set normal contrast levels like in High Sierra. Granting access only to standby database One of the physical standby databases in my environment is open in read-only mode and used for reporting purposes . I want to give users access only to this particular standby, not to primary db.   The best approach I found so far is to create AFTER LOGON ON DATABASE trigger which checks v$instance (or maybe v$database), and throws error for depends on  values of host_name/instance_role columns  .   I wonder if there is a better way to do it. Two spacecraft pilots travel at light speed, meet back on Earth in different era due to time dilation I've been looking for the name of a sci-fi romance book about space travel but haven't been successful so far. I came across it a few years ago, read the plot on its back cover but didn't read the book. It is about two spacecraft pilots, a man and a woman, who travelled at light speed (or maybe FTL, I can't remember) in separate ships. Every time they return to Earth, centuries have passed on Earth because of time dilation. They meet each other for a few times on Earth in different eras, but don't know when, if ever, they will meet again. I don't know how it ends.   If anyone knows which book I'm talking about, could you please tell me the name? Thanks a lot! Probability of a player winning before another Given a 7 sided dice, 2 players roll it independantly simultaneously and when a player rolls a '6' he gets a prize.  What is the probability of the first player getting a prize before the second?  So my solution is to sum over all the turns j in which player 1 could win, and make the second player lose all these turns:  $$P(A) = \sum_{i=1}^{\infty}(6/7)^{j-1}*(1/7)*(6/7)^j = 0.461$$ My question is if my solution is correct, and if so, why is the probability so low? It seems to me that either player 1 wins before the 2nd or the other way around, and the probability of them playing forever is 0, so it should be 0.5? Calling a Java method with no name Where can I get a Thunderbolt hub or splitter? Apple has just announced the new MacBook Airs, Mac mini, and Thunderbolt display. One of the features of the Thunderbolt display that caught my eye was its ability to daisy-chain two displays together from one Thunderbolt port (on a MacBook Pro).  I already have two 24" monitors and I don't feel like paying for two £900 displays. I worked out that all I need is a Thunderbolt hub/splitter so that I can plug the two cables that emerge into mini DisplayPort-to-DVI adapters.  Does anyone know of any Thunderbolt hubs or splitters? Or does anyone know of an alternative method? Expected area of the intersection of two circles If we pick randomly two points inside a circle centred at $O$ with radius $R$, and draw two circles centred at the two points with radius equal to the distance between them, what is the expected area of the intersection of the two cirlces that contain the origin $O$. How to generate random points on a sphere? Limit- almost finished, however hint needed. Converting spoken word audio files into text I've been working on transcribing a lecture series from audio to text files.  There are just over 20 lectures, and each one is about an hour long.  Using VLC Player, I'm able to slow down the speaker's words to a rate that I can keep up with.  However, it's extremely slow going, and it takes so much concentration that I can barely get through a third of a lecture before I have to take an extended break.  The thought had occurred to me that I would be better served by using some kind of speech recognition software, and then proofreading the computer-generated result.  This is likely to be a one-time thing, so while I don't mind using commercial software to get the job done, it would be preferable if it wasn't too expensive (or free; free is always good).  Command-line solutions are fine, too (:  Any suggestions? error in python d not defined. Arabic Stack Exchange? I have been learning some Arabic mostly for fun. I am looking for the Arabic Stack Exchange site but cannot find it. I am sure I saw it lying around a few months ago or so. Any idea what happened to it?