Recent content by rnielsen25

This problem set considers (beta-delayed) alpha decay of ##{}^{20}Na##. I'm currently stuck in the following exercise and was hoping some of you could help me in the right way. Thanks in advance! The problem is: c) The experimental spectrum of ##{}^{20}Na## can be found below. Apart from peaks...

Hi, I have an upcoming exam in astrophysics. We have been told to make sure we study all figures and tables, s.t. we are able to explain them. However, I ran into these figures below, in my lecturer's PowerPoint and I do not know where they originate and aren't presented in my book. I'm having...

So I tried to estimate the contraction rate for Betelgeuse using the Kelvin-Helmholtz mechanism. I used it's estimated mass, radius and luminosity. This gave me a contraction rate (dR/dt) around -600 m/s. This rate is a lot faster than the sun's case and corresponds to a lifetime of around 28...

I just started my master's degree and I'm currently taking a course in astrophysics. However, it seems like I have misunderstood what prevents stars from collapsing (I will elaborate below). Why is it, that as soon as a massive star has finished the fusion processes, the collapse will happen in...

Using the generating function for the legendre polynomial: $$ \sum_{n=0}^{\infty} P_{n}(x) t^{n}=\frac{1}{\sqrt{1-2 x t+t^{2}}} $$ It's possible to expand the coulomb potential in a basis of legendre polynomials (or even spherical harmonic ) like this: $$ \begin{aligned} &\frac{1}{\left.\mid...

Hi everyone, I was hoping the internet would be filled with video lectures since lots of universities have been forced to conduct online teaching. However, that doesn't seem to be the case. Therefore I was hoping that some of you know of some great video lectures for nuclear and particle...

I'm studying physics with math as a minor and I'm currently at 4th semester. Don't get me wrong, I love studying physics. But I'm starting to feel that something is missing. Most of my courses are really focused on learning the formalism and technical methods, so we are able to solve different...

Hello guys (and girls), I'm trying to determine the dark phase of a type Ia supernovae. In order to do that I need to calculate the photosphere's velocity. So I'm trying to determine the redshift of the Si II in the spectra, by finding the minima in the absorption line. But what kind of...

Well i just tried working it out entering numbers. Which i think makes more sense to me. If i have 1 mol RCHO, i have 1 mol Cu2O. Then i have 2 mols Fe2+ In equation 3 i still have 2 mol Fe(2+, which means i have 2/5 mol MnO4-. Then the molar ratio between RCHO and MnO4- must be 1:0,4. Which...

Homework Statement Hi everyone, i have a problem. My brain is short-circuited, and it seems like i can't find out the simplest chemistry in the world :D We made this experiment where we should determine the sugar content in potato flour. We added amylases to break down the starch to glucose...

Hi everyone. What you see here is er Fourier spectra. If i want to conclude that there is a statistical significance difference between the peak value around 30 hz, and all the other smaller peaks. Should i do as following. Estimate the mean value as 2. Estimate the mean peak value to around...

I didn't thought about solving k in the diff. equation, and replacing it in that way. Thanks for the help. I think i understand everything now, so i will probably close the thread now.

All right thanks. Could you also help me out understanding, what happens in equation 13,37? Especially what happens with the constant, and why ##\frac{d\Omega}{dt}## appears.

But assuming using finite integrals is okay. Why do they replace k with ##\frac{d\omega}{dt}## but that is probably more a specialized physicist in this field i have to ask?

##\int^{\omega}_{\omega_0}(\omega^{-n})d\omega=\int^{\tau}_{0}(-k)dt## The solution would be, if n has to be 3: ##- \frac{\omega^{1-n}-\omega_0^{1-n}}{n-1}=-k\tau## If you multiply with -1 on both sides, you will se the upper solution, indeed is the same as in the picture. But what if you...