I am confused, Classical wave theory says that Intensity of the light(wave) is the proportional to square of the amplitude. How intensity is proportional to the square of the amplitude?
I often see $I(t)\propto |E(t)|^2$. What is the exact form ? Which constants are missing to make this an equality and why are they so often omitted ?
Can we say that $\frac{0}{0}$ is every number? May I get off in an intermediate city of my route during transfer? I want to go from Panamá to Turkey. There're direct flights of Turkish Airlines that are expensive. And there're flights Panamá -&gt; Istambul -&gt; Baku there're cheaper 2 times of the same airline. The transfer in Istambul takes 6 hours.    Will it be a violation if I buy a ticket Panamá -&gt; Istambul -&gt; Baku and leave in Istambul? How and when should I tell my son that his amazing father isn't his biological father? My son is going on 5 and starting to learn a lot about how we're created. I've been with my husband for 10 years, but nearly 6 years ago I had no other choice but to move 1000 miles away and after trying the long distance thing it didn't work so we split up.   I ended up going through a rough patch and started dating an abusive jerk. After a year I was pregnant. He threatened me trying to force me to have an abortion and I refused. His grandmother was chief of police and he scared me into moving back to Florida.  Eventually, when I was 4 months along in my pregnancy my husband and I picked up right where we left off. He loved me so much and accepted our son as if he was his own and has done an amazing job at raising him.   He enrolled in college while I was pregnant, got us a house and went above and beyond to care for us both (as after giving birth I became very ill due to rare brain and spine conditions). I've always tried to do right by my son. Since day one, even while with my husband, I tried to keep the sperm donor involved. But he wanted no part of his son.  My husband stepped up when the biological father refused. The biological father would pretend that he cared, only to tell me he never cared about him anyway and was just trying to manipulate me into stopping child support (which I did anyway after the first year: I felt it wasn't right to take his money when my son had a dad who loved, supported and wanted him from the beginning).  This is a very long story so I'll try and make it not so much of a novel. The sperm donor has made it very clear he wants nothing ever to do with my son. My husband has been Dad since the moment my son entered this world. I've always planned to tell my son as early as possible. I think now, or in a few years, it won't be as hard on him compared to us telling him when he's a teen and who knows how he'd handle it.   I just don't know what to do. We have an extremely happy loving family. My son adores his dad. We never argue, we have a very happy non-dysfunctional marriage. I just feel we have a very special family. But I refuse to lie to my son. What if we wait and someone else maliciously tells him? Or if, when he's older and finds out, he spirals out of control?  I'm so confused, I just want to do the right thing and desperately need advice. Especially from others who have been through similar circumstances. We're planning on meeting with therapists and I guess child development specialists, if someone could also point me in the right direction for what type of doctor is best suited in this situation.   Also my son is very happy. He has a wonderful life and I feel as if he would do fine, knowing how much he loves his dad and just beginning to really grasp the concept of life. I don't think it would change anything for him, if that makes sense. I've been worrying over this for 5 years and really need some answers! Do professors get paid for supervising students? "Can't find Project or Library" for standard VBA functions How to print line numbers to the log. Say when outputting some information to the log, I also want to print the line number where that output is in the source code. As we can see in the stack trace, it displays the line number where the exception has occurred. Stack trace is available on the exception object.  Other alternative could be like manually including the line number when printing to the log. Is there any other way? Is there a quick way to get the control that's under the mouse? I need to find the control under the mouse, within an event of another control.  I could start with GetTopLevel and iterate down using GetChildAtPoint, but is there a quicker way? Finding my house in minecraft Using a comma before "but" How to load JAR files dynamically at Runtime? Replace unknown reference (?) with the tag from \ref or \cite While working on a document, it would be helpful if instead of a ? for unresolved references or citations the tag used in the \ref{thisthings} or \cite{Bloke1978} could appear instead.  Is there a package that turns on this behaviour? How can one cite theorems of references? I would like to cite the item (iii) of proposition 3 of a reference. How can I do it? Which ways do you suggest? This is a question not only about LaTeX, but also about style. One option I have seen to cite pages of a reference is \cite[p.~333]{Audet}. Is there something similar to cite theorems, propositions and so on? Install Biber in MiKTeX on a 64-bit version of Windows Update: As of summer 2015 Biber is also included in the 64-bit repositories for MikTeX. There is no need to install Biber manually any more, it can simply be installed via the Package Manager just like other packages.   The question  describes how to use Biber with MiKTeX. But on the 64-bit version of MiKTeX Biber isn't installed.  How it is possible to install Biber on a 64-bit version of Windows?  Can I use this ? If $x^{2}-x\in Z(R)$ for all $x\in R$, then $R$ is commutative. What are some strategies that I can employ to handle a power gamer that constantly outshines the rest of the party? This is a friend of us all and we don't want to boot him, but combat simply isn't fun when the party has nothing to do while he mops up an encounter by himself. How do I bypass "this connection is not private" warnings in safari? Prove that $T$ has a cyclic vector iff its minimal and characteristic polynomials are the same How to enumerate an enum How can you enumerate an enum in C#?  E.g. the following code does not compile:  public enum Suit {     Spades,     Hearts,     Clubs,     Diamonds }  public void EnumerateAllSuitsDemoMethod() {     foreach (Suit suit in Suit)     {         DoSomething(suit);     } }   And it gives the following compile-time error:     'Suit' is a 'type' but is used like a 'variable'   It fails on the Suit keyword, the second one. What happens if a Rainbow Servant takes levels in Mystic Theurge? When a Rainbow Servant hits level 10 they gain access to all nondomain Cleric spells. All spells that do not appear on any other spell list they have are cast as Divine spells. This means that, if they have the skills and have learned 2nd level spells, they qualify for the Mystic Theurge Prestige Class.  But what happens when you actually start to take levels in it? The text says:     When a new mystic theurge level is gained, the character gains new spells per day as if he had also gained a level in any one arcane spellcasting class he belonged to before he added the prestige class and any one divine spellcasting class he belonged to previously.   What it does not say however, here or elsewhere, that these classes have to be different classes. Do you get one level in Wizard/Warmage/whaever for being an Arcane caster, then ANOTHER level for being a Divine caster as well? The text for the Rainbow Servant says the following:     Such spells are cast as divine spells if they don’t appear on the sorcerer/wizard or bard spell lists.   So it comes down to these questions:   Does being able to cast Divine spells qualify you as a Divine Caster, or is there more to it than that? If it is, what happens when you take levels in Mystic Theurge like this? Do you go up one level or two? What happens if this means you go over 20th caster level? Do you keep gaining spell slots like a level 20+ character, or does something else happen? What is the point of Refresh if Dynamic has an UpdateInterval option?