All I made up in my mind about light beeing a wave  traveling at vertain speed, made me thing of it like something we could store in tehory.  So I would assume if I had a box where the inside is made up completly with mirrors, when sending light in and closing the box, this light would keep traveling inside the box, beeing reflected by the mirrors untill we release it again.  But afaik this isn't the way it is. So how does it come? Why isn't light working this way?
For what longest possible time it was possible to hold light in a closed volume with mirrored walls?   I would be most interested for results with empty volume but results with solid-state volume may be also interesting.
Does Android hide some amount of RAM from the User? I bought a new tablet, but Android (2.3.1) shows that it has only 150MB free of 256MB, and it should have 512MB.  I checked the file /proc/meminfo, MemTotal information. It only shows 256MB. Is there a possibility that the Android "hid" 256MB of RAM from the user? Can I use older MySQL workbench with newest MySQL server? MySQL newbie here.  I'm using Ubuntu 16.04 (64-bit). I've successfully installed MySQL Community Server 5.7 and MySQL Community Workbench 6.3.  Unable to find these answers in the MySQL forums. I've asked this on Stack Exchange and it was suggested that I ask here instead. I've searched on Ubuntu Forum and here also but did not find an answer. One would think they are common questions but maybe not. Additionally, I cannot find a way to ask a new question on the MySQL Forum. I've spent a ton of time reading/researching/installing/uninstalling and reinstalling MySQL and community workbench on Linux Ubuntu 16.04 (64-bit) and do not want to lose the momentum I've gained. I'm actually making forward progress after a week or so of trial and error working on this up to a few hours per day. It appears that I cannot load MySQL Community Workbench 8.0 without Linux server installed. That seems to be one of the requirements if I understood correctly.  Can anyone tell me if MySQL Community Workbench 6.3 will work with MySQL Community Server 8.0 on Ubuntu 16.04 (64-bit)? I would still like to upgrade and use MySQL community server 8.0 if I can.  Can I use MySQL Community Server 8.0 on Linux Ubuntu 16.04 32-bit?   I've spent many hours googling it and looking on MySQL Forums but couldn't find the answer. Thanks much. ...Rick So, for my science fair I had to test the gauge of a copper wire vs electrical resistance. What I did was I set up a series circuit involving a 6v battery, a light bulb, a multimeter, and a voltmeter. I would change out three different wires with three different gauges.   For the 4-gauge wire, I got 0.004V and 0.04A. For the 8-gauge wire, I got 0.003V and 0.04A For the 12-gauge wire, I got 0.001V and 0.04A.   In this experiment, what would the independent and dependent variables?  We also have to fill out a table like this: How do you end with a single quote followed by a double quote? Why is there no article in "We are Family"? Is there a reason, beyond historical reasons, that three phases has become the dominant number of phases?  I am aware of the advantages against one phase and two phase, namely the reduced amount of conductor needed, and that motors can provide torque when stalled (and less pulsation).  Is this solely due to diminishing returns, with only a small increase in smoothness of torque application, at the cost of increased complexity (increased number of wires (albeit of smaller CSA)).  To be clear, the phases are all evenly distributed, that is, five phases separated by 72 degrees. Different methods of evaluating $\int\sqrt{a^2-x^2}dx$: Is there a simple and nice way to solve $\int\sqrt{a^2-x^2}dx$:  PS:I am not looking for a substitution like $x=a\sin p$, How do I write a short literal in C++? Very basic question: how do I write a short literal in C++?  I know the following:   2 is an int 2U is an unsigned int 2L is a long 2LL is a long long 2.0f is a float 2.0 is a double '\2' is a char.   But how would I write a short literal?  I tried 2S but that gives a compiler warning. Why does my item name not show up in 1.13? Start modal operator from a click in panel I want to start a modal operator by clicking a button in a panel in the properties region. It should then stop when I click somewhere in the 3D viewport. I want to execute some code when I start and finish the operator (see the code below). I tried modifiyng the modal operator template with an execute method to start the modal operator. But the now the context.space_data.type is always &quot;PROPERTIES&quot; because that's where the panel is located, I guess. Is this a bad way of doing what I want? class MY_OPERATOR_OT_click_on_3dview(bpy.types.Operator):          bl_idname = &quot;mesh.click_on_3dview&quot;     bl_label = &quot;Click on 3D&quot;      def modal(self, context, event):                  if context.space_data.type != 'VIEW_3D':             return {'PASS_THROUGH'}                  if event.type in {'MIDDLEMOUSE', 'WHEELUPMOUSE', 'WHEELDOWNMOUSE'}:             # allow navigation             return {'PASS_THROUGH'}         elif event.type == 'LEFTMOUSE':             # DO ALL THE POST-SELECT STUFF             return {'FINISHED'}         elif event.type in {'RIGHTMOUSE', 'ESC'}:             return {'CANCELLED'}          return {'RUNNING_MODAL'}      def execute(self, context):         # DO ALL THE SETUP STUFF           context.window_manager.modal_handler_add(self)              return {'RUNNING_MODAL'}            def cancel(self, context):         print(&quot;CANCEL???&quot;) Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization? From what I understand, the  states that there is a fundamental natural limit to how accurately we can measure velocity and momentum at the same time. It's not a limit on equipment but just a natural phenomenon.  However, isn't this just an observational limit? There is a definite velocity and momentum, we just don't know it. As in, we can only know so much about the universe, but the universe still has definite characteristics.  Considering this, how do a wide range of quantum mechanical phenomena work? For example, quantum tunneling - its based on the fact that the position of the object is indefinite. But the position is definite, we just don't know it definitely. Or the famous light slot experiment? The creation of more light slots due to uncertainty of the photon's positions?  What I am basically asking is why is a limit on the observer, affecting the phenomenon he is observing? Isn't that equivalent to saying  because we haven't seen Star X, it doesn't exist? It's limiting the definition of the universe to the limits of our observation! How would one write object-oriented code in C? Timeout on a function call I'm calling a function in Python which I know may stall and force me to restart the script.   How do I call the function or what do I wrap it in so that if it takes longer than 5 seconds the script cancels it and does something else? Is natural projection a natural transformation? Proof of $\int_0^\infty \left(\frac{\sin x}{x}\right)^2 \mathrm dx=\frac{\pi}{2}.$ What is the integral of $\int e^x\,\sin x\,\,dx$? I'm trying to solve the integral of $\left(\int e^x\,\sin x\,\,dx\right)$ (My solution):  $\int e^x\sin\left(x\right)\,\,dx=$  $\int \sin\left(x\right) \,e^x\,\,dx=$  $\left(\sin(x)\,\int e^x\right)-\left(\int\sin^{'}(x)\,\left(\int e^x\right)\right)$  $\left(\sin(x)\,e^x\right)-\left(\int\cos(x)\,e^x\right)$  $\left(\sin(x)\,e^x\right)-\left(\cos(x)\,e^x-\left(\int-\sin\left(x\right)\,e^x\right)\right)$  $\left(\sin(x)\,e^x\right)-\left(\cos(x)\,e^x-\left(-\sin\left(x\right)\,e^x-\int-\cos\left(x\right)\,e^x\right)\right)$  I don't know how to complete because the solution gonna be very complicated. How does Java's PreparedStatement work? Named parameters in JDBC I've deleted a system file from my Mac and need to get it back.  System files can include:   hidden files in the root of / - especially unix files in /private  /System files /Library files /Applications files that ship with the core OS   System files are not any app, user files or files that can be regenerated by a known sequence such as cache files, Spotlight index files, etc…    Canonical question and answer for . I want to get records from custom object sort by a field as number. The field I want to sort is string type. Is there any way to do that? I am storing result in list, is there a way to sort list based on the string field but sort it as number?