Recent content by catkin

Homework Statement This is a personal enquiry, not a homework question. I think I understand but would like confirmation. In a modified Thompson's Jumping Ring apparatus, the solenoid is horizontal and the ring free to move on the iron core. If the ring is either side of the central...

Thanks for that; it's the closest I've found to a satisfying explanation but I'm still curious. How wrong is the following wild theorising? The photon is a probability density wave function, not actually manifested at any place along that wave function until it interacts with another...

Hello :smile: It's taken a while ... here's the diagram that makes my original question make sense. Best Charles

Thanks again Tom :smile: Oops! I tried to work out whether sqrt(E^2 - m0) is E or whether it is just a coincidence that it gives the same number. Presumably coincidence because the erroneous calculation is dimensionally inconsistent. Best Charles

Thanks Tom :smile: OK with ss not being possible because of spin considerations but can you recheck the calculation? I just pasted sqrt(249^2 - (0.15 * 938)) into gcalctool 5.22.3 and got 248.71730941 again ... Best Charles

Thanks Tom :-) Duh! I didn't consider that it might be an electromagnetic force interaction! We've been so focussed on weak and strong I missed the obvious. Best Charles

You are more likely to get an answer if you follow the proforma question layout and give a bit more information, say about what field of Physics you are asking about and the meaning of the symbols.

Homework Statement Hello :smile: The question is from "Advanced Physics" by Adams and Allday. It is from section 9 "The Physics of Particles", "Practice Exam Questions". It is question 11, part c. The level of this study is between school and University. Figure 9.5 represents a simple...

Hello :) Here are two suggestions for improving the data entry screens when posting a new question. When "Preview Post" is used it adds another set of proforma headings. How about not doing so? How about changing "You may add 5 tag(s) to this thread" to "You may add 5 comma-separated...

Homework Statement The question is from "Advanced Physics" by Adams and Allday. It is from section 9 "The Physics of Particles", "Practice Exam Questions". It is question 10. The level of this study is between school and University. I am uncertain about the answer to part c, ii (3rd...

Thanks Redbelly :) The relativistic/Newtonian choice is something of a judgement call on this one. In our studies so far we have chosen 1% discrepancy in the result as the (arbitrary) determinant. On that basis, we found the cut of point for electrons is ~25keV acceleration. This is...

Thanks Redbelly and Andrew. Sorry it has taken me so long to get back here. Helpful points, both about choice of unit and working out early on that the extra complexity of a relativistic approach is unnecessary. What is the rest mass to K.E. ratio heuristic that allows deciding a...

Homework Statement The question is from Advanced Physics by Adams and Allday, section 8 Practice Exam Questions, question 30. Estimate the de Broglie wavelength of an electron that has been emitted thermionically in a vacuum from a filament and then accelerated through a p.d. of 30.0 kV...

Thanks, they are very good but better for reference than for introductory learning. For the record, Electricity and Thermal Physics by Ellse + Honeywill has turned out to be good for introductory learning. It covers the Excel A-level optional topics as well as the material of its title. I...

That would be very welcome. We are studying Particle Physics as an optional extra part of the British A-level. It is intended to take students planning on studying Particle Physics at first degree level that little bit further. I've spent a long time looking on the Internet and found almost...