Element Definition and 881 Threads

Homework Statement Prove that in any group, an element and its inverse have the same order. Homework Equations none The Attempt at a Solution I know that I need to show |g|=|g^-1|. This is how I approached it but I'm not sure I'm right, it seems like I'm missing something. Let...

Since atoms above a certain atomic number are unstable and have an extremely short lifespan, then the atoms of the unknown element that comprises the mass of a collapsing star in the process of becoming a black hole just before the stage where a singularity is achieved should by all accounts...

Hi there, I have completed my analysis in BEM. The results gives me velocity potential in form of 37954305E-04 +1.58625295E-06 +2.10275811E-07 +... I have real scattering values, imaginary and absolute scattering values in this form. I am new to the method and from a different...

Unable to "decrypt" emission/absorption matrix element Hi to everyone! I'm reading an example of atom radiation interaction (more precisely, an atom emits a photon which photoionizes another atom) on an old book (60s) and I'm facing a matrix element which I never saw. I mean, I'm not able to...

When using BJT as a pass element in series pass regulation, why is the NPN drop more than the PNP. Both have BE diodes. Why is the drop (VCEsat+VBE) in case of NPN and drop is equal to VCE sat in case of PNP. Can someone also explain VCE sat using diode equivalent of BJTs.

Homework Statement Determine whether the operation has an identity element. x*y = 3xy Homework Equations e*x = x*e = x, if this holds, e is an identity element The Attempt at a Solution My attempt: x*z = z*x = 3xz, then 3xz = x <=> z = 1/3 => e = 1/3. But the answer key in the...

Homework Statement Light emitted by Element X passes through a diffraction grating having 1200 lines/mm. The diffraction pattern is observed on a screen 75.0 cm behind the grating. Bright fringes are seen on the screen at distances of 56.2 cm, 65.9 cm, and 93.5 cm from the central maximum. No...

hi guys I am looking to find a source of radiant heat about 2 inches wide and 6-8 inches long and i got to thinking if i hook up 8 AA batteries in series it should produce 12v needed to power the element of a water heater, my question is will this power source work to run the element? thanks

Homework Statement Let R be a commutative ring with unity and S a subset of R which is closed under multiplication. If P is a maximal element of the set of ideals which do not intersect S nontrivially, then I want to show that P is a prime ideal of R. Homework Equations The...

do suggest a good book for finite element method?some books have left me confused over the various methods

Curious question, figured what better place to ask than the physics forum. So I just picked up a used hot tub. Was running great when I bought it. Filled it up with water, turned it on, started its cycle. It can take over 24 hours for the tub to reach 102 degrees. There's a 12 inch...

Homework Statement Construct a finite field of order 16. And find a primative element. Homework Equations The Attempt at a Solution What I did was find an irreducible polynomial in Z/<2> of degree 4. I used f(x)=x^4+x+1. Then I took a to be a root of f(x) and set a^4=a+1...

I'm finding it hard to frame my question in the right words as I'm an English learner. So, I hope you would be able to get to the main point using your own understanding and interpretation. Thanks. When I was a kid I used to love playing video games. I think I still would love to but couldn't...

Homework Statement http://img137.imageshack.us/img137/355/circuit2.png Homework Equations P=VI P=I^2 R V=IR The Attempt at a Solution The part a is all correct. i_\wedge = 5A i_o = 2A v_o = 80V This is what i have done in part b but it is not correct because P_delivered not equal to...

Hi all, I have question regarding to heater I want to build. It suppose to be a heater used for soldering a thin copper sheet (1mm thick) with other small copper components. Heater has to be flat as much as possible and reach the temp up to ~250C (solder melting point). The copper sheet...

Researchers have found seismic evidence for a 300 km thick layer in the outer core formed of light elements expelled upon inner core solidification. They believe the gravitational energy released by this compositional convection is a key input to the energy that drives the geodynamo...

Hi, Is there a way to associate each element with its row and column number without explicitly doing each one in turn? I have a matrix and I want to multiply it by a matrix whose elements are a function which takes as its input values the row and column number of the first matrix. (I think...

Homework Statement Given a a group of order 30 w/ a non-normal Sylow 5-subgroup, the problem is to count the number of elements of orders 5, 3, 2, and 1. Homework Equations The Attempt at a Solution I understand the Sylow theorems and can use them to show that there must be 24...

I think that I just noticed something that I probably should have noticed a lot earlier in my Abstract Algebra class: If G is a group which contains some g of finite order, then by definition g^k=e for some integer k. Does this mean that each element of finite order in G can be written as...

Find <nlm|(1/R)|nlm> for the hydrogen atom (nlm = 211), R is just the radial position Operator (X2 + Y2 + Z2)½.

Homework Statement The half life period of N-13 is 10.1 minute. Its life time is ------- The answer has been given as infinity. Could someone help the formula to arrive at this answer 2. The time taken by the radio active element to reduce 1/e times is ----- The answer has been given as...

Is the following property exclusive to the identity elements: a- = a (inverse of a = a)?

Hi, I'm reading Sean Carroll's text, ch2, and believe I understood most of the discussion on Integration in section 2.10. However in equation 2.96, he states that \epsilon\equiv\epsilon_{\mu_1\mu_2...\mu_n}dx^{\mu_1}\otimes dx^{\mu_2}\otimes...\otimes dx^{\mu_n}...

Homework Statement Calculate the general matrix element of the position operator in the basis of the eigenstates of the infinite square well. Homework Equations |\psi\rangle =\sqrt{\frac{2}{a}}\sin{\frac{n \pi x}{a}}...

I've been looking at how people calculate basic things on the lattice. How would you go about calculating a single number? By this I mean decay rate, cross section, amplitude or contribution to an amplitude. The reason I ask is that I've been looking at some lattice QCD code up close. The code...

Homework Statement I was looking through my notes, and I saw that my professor solved a propellor blade problem in a way that I don't understand. I took this class two semesters ago, so I cannot ask the professor himself. The problem that I am having is with his setup of a differential element...

Homework Statement Let {p_n}n>0 be the ordered sequence of primes. Show that there exists a unique element f in the ring R such that f(p_n) = p_n+1 for every n>0 and determine the family I_f of left inverses of f. Homework Equations The ring R is defined to be: The ring of all maps...

I need to construct a heating element powered by 9V that needs to reach 400 C. How do I figure out what length of wire I will need. I will most likely be using nichrome or kanthal A1

Hi everyone, Our digital image processing teacher is now teaching Fourier transforms. He's using MATLAB and using the FFT function to get the Fourier transforms of a signal, but he has also taught us that we can use a Fourier matrix. He finished going through how to form one, but on a homework...

[b]1. Homework Statement [/] Is there a group G with order 100 such that it has no element of order 4? How would one go about proving the existence of such a group? [b]2. Homework Equations [/] For every prime divisor p of a group, there exists an element with order p. The...

Homework Statement I have just started solid state physics course and we got an assignment to choose one element that we are going to work with. Which element is interesting from a solid state physics point of view (and relatively not too difficult to work with)? Homework Equations...

So X, Y = non-empty sets, and f = function (X,Y) I have to show that f(A and B) (c underlined) f(A) and f(B) using element argument. I have no idea - started with choosing x as a particular but arbitrarily chosen element of f(A and B) so now I have to show it is in f(A) and f(B)...

Homework Statement A group <x> has order n. k= nq+r where 0<= r < n. Prove that the order of x^k is n/d where d = gcd (n,k) Homework Equations The Attempt at a Solution I know that (x^k)^(n/d) = 1, but how do I prove that n/d is the smallest one? I tried to assume that...

Homework Statement Let gcd(h,k)=1, o(a)=h, o(b)=k, show that o(ab)=hk Homework Equations o(a)= order of a modulo n o(a)=k iff k is smallest integer, a^k=1 mod n The Attempt at a Solution to prove o(ab) l hk, no problem, just need to show (ab)^{hk}=1 mod n and to prove hk l o(ab), use...

Salutations! I just want to make sure I am on the right track... Homework Statement Let G be a group. Prove that if every element in a group is equal to its own inverse, then G is abelian 2. The attempt at a solution Pick two elements a, b \in \thinspace G. By assumption, a =...

Hi guys, I wanted to know these things with their respective examples : 1. What is an atom ? 2. What is a particle ? 3. Why do we use/calculate the atoms of an element to balance an equation ? Please answer to these questions guys, because I only have 2 days for my exams and to know them.

Is it true that if a finite group G contains a subgroup of index 2, then there is an element of G with order 2?

Hi , I have a question that's confusing and difficult to comprehend " A heating element is placed on the floor and bag of water is placed over it. At present, A power of 300W is applied to the heating element. Peter, the technician, wants to increase the rate at which the water in the...

I am studying for a modterm on Monday and asking for help on the homework questions I got WRONG on my problem sets (so I can hopefully improve my understanding and see my mistake). This is my reworked version of the incorrect HW problem and I would like to know if I am on the right track...

Hi guys. I want to transfer each elements of an array (which is declared in one subroutine)to main function using common block technique. When i am doing so i go always a constant value in the array in the main function. Suppose i have one array bparz(i) which has different values in one...

Homework Statement I need to find the inverse to element in 7 in ring Z_{13} Homework Equations 7^-1 in Z_{13} The Attempt at a Solution Needs to find X so that, 7x=1 in Z_{13} => 7x=1+k*13 And then my notes was messed up :(

My lecturer used a symbol in class that represents an element being removed from a set to form a new set. Does anyone know what this symbol is?

Homework Statement X={4^n-3n-1/ n belongs to N} Y={9(n-1)/ n belongs to N } Homework Equations then, XUY is equals to X or Y or N or None of these

i understand that everything else is less as they are (in turn) made from hydrogen, but why was so much of hydrogen made in the big bang? i got a feeling because one proton and one electron is stable. (similarly, helium was produced as 2 nucleons + 2 electrons is also very stable) but I've...

It takes an infinite time for complete decay of a radioactive element. but on the same time we calculate the half life of radioactive material i-e T-1/2 = ln 2 / lamda. is that means that if we double the half life time we could reach the total life time of radioactive decay so on contrary we...

I want to build something like http://www.radioshack.com/product/index.jsp?productId=2911246", but much smaller and only heating a coil up to 185 C. It would need to last at least an hour, but be as compact as possible. Any suggestions?

Hello all, I am trying to create a simple finite element program in C++ and have been able to build and assemble the GLOBAL stiffness matrix as well as the load vector. I want to apply the boundary conditions using the elimination approach, can anyone tell me how to do this? I am sorry for...

Can anyone see what's not right? In the phase space calculation of a 2 to 2 process I get to I=\int dp_1d\Omega \frac{1}{(2\pi)^2}\frac{p_1^2}{2E_12E_2}\delta(E_1+E_2-E) then I use p_1=\sqrt{E_1^2+m_1^2} \Rightarrow dp_1=\frac{E_1}{\sqrt{E_1^2+m_1^2}}dE_1 thus I = \int dE_1d\Omega...

Hi everyone, I'm currently working on coding a finite element heat problem in Matlab that is as follows: I have a cross section of a beam made of an isotropic material (concrete) that is placed in a furnace, and the outside temperature is raised at a constant rate. I am interested in...

In consideration of a lone wire element of differential length dL carrying a current I: Two things concern me here: 1) Is a magnetic field generated by current I really limited to only spaces that exist orthogonally to the line between the two ends of the wire element? If not, what does...