I'm a hs student studying for an olympiad with this book, and I wonder how much further is physics taught in an undergrad class.

I have to choose two optional modules for my second year of my theoretical physics degree.

I’m torn between these selections:

-Electronics and Nuclear Physics and Neutrinos -Electronics and Structure in the Universe -Nuclear Physics and Neutrinos and Structure in the Universe

I’m considering the electronics option as I can’t select it at any point in my degree and I’ve been informed that having an electronics knowledge may diversify and give me an edge as a theorist

However I don’t know if it’s worth sacrificing the other module for it as well as the fact that no modules have electronics as a prerequisite in later years but they do for the other two

Any input would be valuable

In the derivation after equation 2.5.It says work done by external force from r' to r'+del(r').But potential is defined as work done by external force in bring a unit +ve charge from infinity to a point P with position vector r from the origin.

So why r'+del(r') shouldn't it be r'-del(r')?

https://preview.redd.it/ddkrjypf0bge1.png?width=1339&format=png&auto=webp&s=67db29b294b48155160534c6dabd0bf8cf624b97

The answer key talked about proportionality but I didn't understand at all, can someone please help thanks 🙏🙏

In this example from kleppner, the centre of mass is assumed to be halfway up the quarter-circular rod, but shouldn’t it be where the blue dot is and hence we would end up in a larger torque because of the weight because the force would be shifted a little away from point B? Point B is where we’re measuring torques from.

I am afraid of not doing well in my physics 1 course. So, i am wanting to grab a college textbook on it that i can self teach so that when im in class, i hopefully will know more of whats going on.

I live in the us

Was accepted to the summer school and internship program. I am still waiting for the list of projects to send them my preferences list, but ofc it's just a formality now.

Who else got their offers, let's connect!

I'm returning to college after a hiatus and I am embarrassingly bad with computers. To the point where in waves and vibes today, I had to ask how to run a code ChatGPT generated for me. So I learned about the existence of Google colab this morning, but I'd like to stop getting caught unaware like this. What are physics students using to do coding and modelling? I know I have to learn LaTex for my capstone and thesis, but is python a good language to learn for other things? I'm stumbling around in the dark here, all my high school education included was a typing class in 9th grade.

Evaluating My Equation for LED PAR Efficiency Based on PPFD

Hi everyone,

I’m currently working on a project to calculate the PAR efficiency of LEDs using measured PPFD values. I’ve derived an equation for this purpose, but I want to make sure it’s theoretically sound and practical for real-world applications.

The general idea is to determine how efficiently an LED converts electrical energy into photosynthetically active radiation (PAR), based on PPFD measurements taken with a spectrometer.

Here’s the equation I came up with:

https://arachnoid.com/latex/?equ=%5Ceta%20%5C%3APAR%5C%3A%3D%5C%3A%5Cfrac%7BMppfd%5C%3A%5Ccdot%20%5C%3A10%5E%7B-6%7D%5Ccdot%20%5Cleft(%5Cfrac%7Bh%5Ccdot%20%5C%3Ac%7D%7B%5Clambda%20%5Ccdot%2010%5E%7B-9%7D%7D%5Cright)%5Ccdot%206.10%5E%7B23%7D%5Ccdot%20%5Cleft%5B%5Cpi%20%5Ccdot%20%5Cleft(d%5Ccdot%20%5C%3Atan%5Cleft(%5Cfrac%7B%5Ctheta%20%7D%7B2%7D%5Cright)%5Cright)%5E2%5Cright%5D%7D%7BLEDpower%7D

or

LateX : \eta \:PAR\:=\:\frac{Mppfd\:\cdot \:10^{-6}\cdot \left(\frac{h\cdot \:c}{\lambda \cdot 10^{-9}}\right)\cdot 6.10^{23}\cdot \left[\pi \cdot \left(d\cdot \:tan\left(\frac{\theta }{2}\right)\right)^2\right]}{LEDpower}

I’d appreciate any feedback on its validity, potential improvements, or alternative approaches. Has anyone here worked on similar calculations? Are there specific pitfalls I should watch out for?

Thanks in advance for your insights!

https://preview.redd.it/6locmi2in7ge1.png?width=721&format=png&auto=webp&s=5a3f570c2bd8038584db282073e41d5235117b43

can someone pls explain why the potential energy increases. I understand why it increases form the math because it goes from -U to + U but what does it mean for potential energy to negative or Positive.

https://preview.redd.it/fmowev69m7ge1.png?width=769&format=png&auto=webp&s=1886b4371063077fa10551420c0522d558514b60

In the image, you can see a light clock.

• On the top left, the clock is stationary, and a photon moves straight up and down between two mirrors.
• On the right, the clock is moving at a constant speed, so the photon follows a diagonal path as it reflects between the mirrors.

What I don’t understand is why the time ratio is given as:

Ts/Tm = D/L

where:

• Ts is the time for the stationary clock.
• Tm​ is the time for the moving clock.
• D is the longer diagonal distance traveled by the photon in the moving frame.
• L is the shorter vertical distance in the stationary frame.

Shouldn’t it be the opposite, like this?

Ts/Tm =L/D

Since L<D, this would mean the moving clock ticks slower, which makes sense for time dilation. But why is it inverted in the derivation? Am I missing something?

Would love to hear your thoughts!

I'm a third year physics major taking second semester mechanics and I decided to stay behind and ask my professor a question about the homework. I should also note I'm about to begin working with this professor on a research project, so it's more than just a random prof and the relationship actually matters. The last bit of context is that I am extremely, extremely, grossly anxious to the point where it makes it hard to think and remember even basic things.

So I ask him about setting up an equation of motion and his first question is, well what is the Lorentz force? Something everyone obviously knows...it's literally the most basic freshmen physics. Yet, I couldn't remember and wanted to go back into my notes. At this point he's already looking at me with a raised eyebrow. From here it's just exponentially downhill. He is explaining things to me and I don't really understand what he's saying, and neither do I understand what I'm exactly asking anymore, and he's getting irritated with me.

We get to his office and he's just grilling me on basic knowledge and at this point I am completely overwhelmed by my social anxiety. I'm not writing down things properly, I'm not understanding what he's saying, he's getting irritated which just makes it worse for me. He's just asking me the same question over and over, saying the same things over and over without changing it. Like, I didn't understand that he gave us the E field in the homework and he kept saying "I gave you the E field. I told you what the E field is. What is the problem? What is the E field?" and I'm just like ? When? There was a lot of pedantic things too...like I was trying to ask if these objects interact with each other in a certain way and he'd say "Yes, obviously they interact, of course they interact through the spring, why wouldn't they?" like obviously dude we have been doing oscillators since first sem mechanics, that isn't what I'm asking.

Eventually he says, "there is something you are overcomplicating and I don't know what it is". Which, I mean yeah I agree, but he goes on to say, "This is a simple course...it's classical mechanics. it's supposed to be easy" which is nonsensical because otherwise an 80% wouldn't be an A and like 60% of the class wouldn't be saying it's difficult.

I'm just so embarrassed to the point where I don't want to do research with him or he in the same classroom together.

Thank you if you've made it this far

Just wanted to add an edit that I appreciate everyone's responses. You guys have been so positive and it's been helping me feel better, so thank you.

I literally don’t know how to do this question. I’ve found work done using 1/2 mv^2 as 652J but I don’t know where to go from there. I’ve been playing around with W=Fs and stuff but I just don’t know how to get the force value

https://preview.redd.it/nhki8o2or6ge1.png?width=711&format=png&auto=webp&s=2eb8313e4452c8686754c61196c4cb648238afdb

Pls help me understand ( i am new to phys 2 so pls make the explanation ez) Why would the PE be higher at B. I know that Volt gets lower as you go along the e field lines so would that not mean PE gets lower cus V = Pe/q. Thanks

I am a high school student particularly interested in physics and math. I've decided to take part in something I would call a scientific exhibition and chosen quantum computers as a topic which was supported by my teacher. It is really rigorous and mostly for students in the last grades of high school (18-20 year olds, I am from central Europe and we have a bit different school system), so I need to work quite hard to compete with students who are older than me. However, I gained a lot of physics and math knowledge outside of school and that helps me a lot.

The problem is that the work should consist not only from theoretical part, but should also contain practical results of our own observations and research in form of statistical analysis, computer program, machine or tool designed and created on our own etc. Than it all needs to be covered in an essay together with our theoretical knowledge. Its almost at the level of diploma thesis written by university students.

My teacher has been out for quite some time now because of illness and that's why she doesn't really advice me on how to progress with my work. So far, I have written out all of the physics theory regarding quantum computing and its principles and also added some descriptions of the most recent discoveries in this field. What I need now is a good topic or a problem that I can solve with my skillset and limited access to real research (only our school lab and Quiskit from IBM).

I have been experimenting with things like writing a code for breaking RSA (but I am clueless about its real benefit and functionality) or solving various math problems like generating a random numbers and so on (all using Quiskit). I need something that I can actually write a lot of things about and explain how it could be beneficial now or in the future. Using a Shor's or Grover's algorithm to solve some real life problem is a good example of that (but I have no idea where to find a problem it could be applicable for). It shouldn't require any tools that are out of the reach of us "mortals" and it would be great if it can be done in a shorter time frame (2 weeks max).

I hope I have expressed everything in an understandable way and that this is the right place for posting this. My mathematical understanding is pretty good, but programming sometimes needs a bit of correction and help. I am not a native english speaker, so if there are any unclear things in this post just let me know.

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My equals: currently high school senior about to graduate in couple of months and would like to persue bs(4 year) in physics.

My question is, does the college we do our undergrad in physics matter if we want to join grad school for phd or ms? I am 100% sure that I will get atleast masters in physics even if I were to divert to other fields like software or something, so this question is really important for me. Provided I work my ass off (perhaps what every physics guys do,lol) in bs, can I grab grad school admissions? Would it matter in long term if I were to join as assistant professor or some other position appropriate to my qualifications?

Any advises/insights from those who have persued bs/bsc from local "not much know college" and later on went to good reputation universities, or had landed faculty positions would be highly appreciated.

So Im a masters student and I gave a seminar about some simulations Id been running. One of the results I got was a weird value, but my supervisors and all the post docs watching thought it was really interesting and could be explored a lot. So they reinforced my belief in it and I kept justifying the result in various ways.

I thought that they wouldve just said that looks weird you should check it over, but they believed it was real. I was like theres no way my dumbass actually discovered something, and then I realized after that I was plotting the wrong values. So we had an almost 2 hr discussion for nothing, my question is how do I break it to them and has this happened to any of you guys?

I’m currently in my second year of university studying physics. When I first started my degree, my goal was to pursue a PhD in astrophysics, but I’ve come to realise that the financial prospects, especially in the UK, are quite limited.

I genuinely love physics—it’s all I do—but coming from a low-income background, I feel that pursuing a career in academia would be a disservice to my parents. Recently, I discovered the field of quantitative research, and it seems like an excellent alternative. It offers strong financial prospects while still allowing me to engage in complex problem-solving, which is the main reason I enjoy physics in the first place.

The only issue is that I have no background in finance at all. Given my current situation, what would be the best way to break into the field? Any advice would be greatly appreciated. And any physicist that have broken into quant how did you find the transition? Do you enjoy it?

Hi!

I completed my bachelor in computer science 2 months ago and have been working in cybersecurity from the start of an internship until now (6months).

I am planning to go back to university next year to complete a bachelor in theoretical physics majoring in astrophysics. I already did a year of Astro before switching to computer science so hopefully I can transfer some credits, fine if not.

Anyway, I’m doing this because it has always been my passion, and I would be incredibly regretful having not got my degree in it if I was on my death bed tomorrow.

I also want to contribute to something bigger. I have the gift of being able to learn this stuff so I really want to make some kind of impact.

While cybersecurity provides stability, I don’t see myself being truly fulfilled in the long run.

My question is, after graduating theoretical astrophysics, coupled with my degree in computer science, what job prospects am I really looking at?

I do like the idea of working for aerospace companies, maybe some aspect of defence, I’m not really sure yet. I feel quite lost but I do know that I like software engineering and astrophysics.

I’m in Australia if that changes anything but.

Thank you in advance :)

I'd be glad to have anything that will give me intuition on it, preferably a video or graphic

So I have the most theoretical professor ever for my Calc Based Physics 2 course. We’ve gone multiple days in a row in the class and haven’t gone over to actually solve the problems, just how to derive certain formulas and why things work the way the do. We’re all so incredibly lost and struggling with the quizzes that require calculations and problem solving. Does anyone have any advice or resources I can use to help me and my classmates? Thanks.

Good evening ladies and gentlemen

Starting physics degree this year, and am wondering what YOUR optimal work flow is for students in uni and how you guys take notes. Trying to get ideas because I have to decide if I should just stick with my laptop and exercise books or if I really need to get a tablet of some sort

I'd like to be able to annotate lecture slides during the lecture but think I will have to print these off for physics notes or just get a tablet which I don't want to do. So what setup do you guys use for learning in lectures? How much of a problem is having notes seperated between exercise books and laptop?

Opinions welcomed, thank you!

burst into tears at school (i need help)

Sites like Stack Exchange discourage uploading images of equations or using specific colors and fonts in images, and for good reason, to make content more accessible to those with visual impairments. Where does this subreddit stand on this policy?

Edit: The point of this post is to ask whether we should implement such terms on this sub as well in order to benefit people with visual impairments.

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Me and two other students in my community college physics two class are planning on completing honors project, which is meant to be one project worked on throughout the semester that goes above and beyond the course material to earn honors credit for the course. We are given lots of freedom on what this project can be, but for a STEM course like this, it’s encouraged to be some sort of experiment or rudimentary original research.

I am a mathematics major hoping to go into astrophysics eventually, and my two partners are both programming majors. Our knowledge is limited on account of the fact that we are still in community college. We do, however, have access to a lab with some decent equipment, such as electrometer and static generators and Faraday cages.

At the moment, we are pretty short on ideas. Are there any experiments you guys know of that we can replicate using our currently rudimentary knowledge of physics, programming, and/or astronomy focusing on physics 2 concepts such as electromagnetism?