What are the effect of electrons on alpha particles during this experiment?  Also why do we neglect them ?
Geiger and Marsden's experiment led Rutherford to believe that the positive charge and most of the mass of the atom was concentrated in a small region. I understand what led him to conclude the way the positive charge is positioned in the atom. But how did he conclude that most of the mass was in a small region (the nucleus)?  How did the distribution of the mass matter after all? Given that the electric force is greater than the gravitational force by many magnitudes, the force between the positice charge and the electrons was predominantly electric.   So how did Rutherford conclude that most of the mass is in the nucleus?
Process management and high technology weapon. Novel name and author? Show that if $a$ and $b$ are positive integers with $(a,b)=1$ then $(a^n, b^n) = 1$ for all positive integers n  Hi everyone, for the proof to the above question,  Can I assume that since $(a, b) = 1$, then in the prime-power factorization of a and b, they have no prime factor in common, when they are taken to the $nth$ power, they will still have no prime factors in common, and so $(a^n, b^n) = 1$ for all positive integers n.  I think I'm jumping to conclusions here again, if so, leave some tips on how to do the proof properly, thanks :)  And also, I do not know how to approach the reverse problem where if $(a^n, b^n) = 1 then (a, b) = 1$, any guidance will be much appreciated! Is "I am sat" bad English? I believe it is incorrect and instead either the present continuous     I am sitting   or the predicate adjective     I am seated   should be used.  I hear this quite often, however, and ultimately usage overrules formality.  Does anybody know where this originated or how to describe it grammatically? Example (note the case):  string s = "Hello world!"; String s = "Hello world!";   What are the guidelines for the use of each? And what are the differences? Do I need a UK or Ireland transit visa when flying from the US to a Schengen country? I am travelling to Budapest and therefore have a Schengen Visa. I hold an Indian passport and a valid US visa. I'm travelling from Chicago-Heathrow-Budapest and returning by Budapest-Dublin-Chicago.  Would I need a transit visa for UK/Ireland?  UPDATE  Hoping this will help someone someday.   I was not allowed to board my return flight (BUD-DUB-ORD) because I do not hold an overnight Irish Transit Visa. They said I could have transited happily if the connecting flight was in the same day, but because I would have to originally land at 10 PM and catch the connecting flight next morning at 10 AM, I needed a transit visa. Well, I thought it was BS, but couldn't help comply with the rules. I booked another last minute ticket and flew via Warsaw via LOT. How do I install Adobe Acrobat Reader from the repository? How do I install Adobe Acrobat Reader in Ubuntu 14.04 using a Trusty apt repository?  This is NOT a duplicate of . In Synaptic &gt; Repositories &gt; Other software I enabled "Canonical Partners", but I still cannot install acroread as it is not available on my 64-bit system.  Here's the output from the console:   root@liv-inspiron:/home/liv# apt-get install acroread Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package acroread root@liv-inspiron:/home/liv# apt-get install acroread:i386 Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package acroread How do I prove the sequence $x_{n+1}=\sqrt{\alpha +x_n}$, with $x_0=\sqrt \alpha$ converges? ( boundedness?) Infinite amount of flags I have been going through some old posts, flagging them as necessary. But I have noticed that the number of posts that I am able to flag is continually staying at ten. It seems that the new flagging system has messed this up.  I am able to keep flagging posts even after 10, so I know it isn't a UI bug. This is a very big problem, because I can flag infinitely many times. And I am pretty sure this isn't the intended behavior of the overlords This isn't because I am being awarded more flags. I flag more than 13 posts in 5 minutes, and I can keep going without restriction  Some of the flags were accepted, so now my number is up to 13. But it is still staying at 13 "Thanks for having me" Recently, I finished my phone job interview with the phrase "Thanks for having me". It was a reply to the other person's "Thank you for your time". So, does "thanks for having me" sound alright in this context? Why do electron and proton have the same but opposite electric charge? What is the explanation between equality of proton and electron charges (up to a sign)? This is connected to the gauge invariance and renormalization of charge is connected to the renormalization of photon field, but is this explanation enough? Do we have some experimental evidence that quarks have 2/3 and -1/3 charges? By the way I think about bare charge of electron and proton. And I am also wondering if this can be explained by Standard Model. Let $A$ be the $\mathbb{C}$-subalgebra of $M_4(\mathbb C)$ consisting of matrices of the form   \begin{pmatrix} * &amp; * &amp; * &amp; *\\ * &amp; * &amp; * &amp;*\\ 0 &amp; 0 &amp; *&amp;0 \\ 0 &amp; 0&amp;* &amp;* \end{pmatrix}   Then how would I find the Jacobson radical $J(A)$ of $A$?    I don't really understand finding the Jacobson radical of $\mathbb{C}$-subalgebras.  Any help on this would be greatly appreciated, thank you! How can I find the possible values that $\gcd(a+b,a^2+b^2)$ can take, if $\gcd(a,b)=1$ Is it possible to add multiple materials to a text object? I know that for a mesh you can go into edit mode and select vertices and assign a specific material to them quite easily. I want to know if it is possible to do this with a Text object (which has no vertices). Every time I try to create a table using MySQL Workbench 6.3 CE it adds "broken" comments at the end of the script.  Example:  I am trying to create a table called "user". This is what the table should look like:   However when I click the apply button, the script generates incorrectly:  CREATE TABLE `user` (   `userid` INT NOT NULL AUTO_INCREMENT COMMENT '',   `record_status` INT NOT NULL DEFAULT 1 COMMENT '',   `createdby` VARCHAR(75) NOT NULL COMMENT '',   `createddate` DATETIME NOT NULL COMMENT '',   `updatedby` VARCHAR(75) NULL COMMENT '',   `updateddate` DATETIME NULL COMMENT '',   `username` INT NOT NULL COMMENT '',   `password` VARCHAR(75) NULL COMMENT '',   `firstname` VARCHAR(75) NULL COMMENT '',   `lastname` VARCHAR(75) NULL COMMENT '',   `email` VARCHAR(75) NULL COMMENT '',   `facebook_userid` VARCHAR(75) NULL COMMENT '',   `email_verified` VARCHAR(75) NULL COMMENT '',   PRIMARY KEY (`userid`, `username`)  COMMENT '');   The comment in this line should not be there, so the code should be:   PRIMARY KEY (`userid`, `username`));   and the code executes when I paste it into an editor and remove this comment. However I create massive databases daily. (Each with +- 15 tables). I can't keep doing this for each table as it is time consuming.  How can I disable this feature that adds the comments to the script? I don't need them in my databases How can I detect if my apple device supports Bluetooth Low Energy I was wondering if it is possible to get a link to a rigorous proof that  $$\displaystyle \lim_{n\to\infty} \left(1+\frac {x}{n}\right)^n=\exp x$$ I'm flying to Tokyo. The flight was sold through Finnair. The first leg is operated by American Airlines. The second and final legs are operated by Finnair.  When I checked in online, it said that some airports on my journey (didn't say which one) don't allow mobile boarding passes?? Meaning I will need a physical copy.  Unfortunately I don't have easy access to a printer. Will I still be able to print all my boarding passes at the airport even though I already checked in online? Under what circumstances can the word "be" be used directly without any change? Possible Duplicate:          2 examples first:  1.It is announced that the accounting class of the 3rd and 4th hours on the morning of this Wednesday be cancelled  2.It is expected that everybody and each household be on guard  Someone told me this kind of examples above appears in the textbook as strict sentences to be taught in the classroom, so is that right for the usage of be  Meantime I looked up the word be at thefreedictionary.com and found one piece of interpretation says :      Archaic Used with the past participle of certain intransitive verbs to   form the perfect tense: "Where be those roses gone which sweetened so   our eyes?" (Philip Sidney).   So is there any connection between the archaic usage &amp; the examples above? BTW, how to understand the short phrase "the 3rd and 4th hours". Many thanks! I was up late working with my red LED headlamp on and when I was looking at the black part of my LCD (Apple Retina Macbook Pro) screen I noticed this interesting diffraction pattern. I'm confused because all I can think of that would cause this are Fourier and Fraunhofer patterns which I thought required more advanced optics the light to be collimated. One friend suggested it might be the polarizer. Any thoughts?  Unfortunately, the picture doesn't show this, but along the x and y axes there were discrete points not a continuous streak. Sorry for the horrible photo quality. Identifying pin numbers from PCB