Physics

Spotted this playing one of my old Pokemon games under the Pokedex entry for Magneton: "It is actually three Magnemite linked by magnetism. It generates powerful radio waves that raise temperatures by 3.6 degrees F within a 3,300-foot radius." That got me wondering how much power that would actually need, and whether it would be feasible for Magneton to actually output it via microwave radiation. Best equation I could find was the heat capacity equation (altered for power instead of energy): P = mcΔT/t (P = power in watts, m = mass in kg, c = heat capacity in J/kg.K, ΔT = temperature change in Kelvin, and t = time in seconds) We know ΔT is 2 K, and …

[edited: now i know conduit spec meaning] [edited] My question was vague, what i want is, wire specs are tested at 1100v , where for example 1.5sq mm copper is rated at 16amp. But my application is 200v, i would guess that lower volt heats up wire faster. so should i use R=V/I to lower amp for 200v ? or the resistance is independent of the voltage.

I have heard that the Big Bang was not an explosion but that everything separated from all other objects (a bit like anti -gravity on steroids?) Could this be an explanation for why there is actually no preferred frame of reference? Every point at the initiation of that expansion period can equally be considered to be the starting point..... Suppose that there had in fact occurred an explosion and that all bodies had receded from a single area radially ,would such a fictitious scenario lead to some preferred frame of reference whereby the site of that explosion could be considered as "ground zero"(and a preferred frame of reference if only o…

Is that only because the actual physical content of any atom and distance between them is so great? If so, given enough stars collapsing to the black hole, can it reach for example couple of meters? Or are there others laws preventing that? Best Regards Ran

One day I was scrolling through youtube and I found a video that was explaining Schrödinger's cat experiment. I personally really like the sound of it and thought "maybe it could be possible?". That was until I went to Instagram and found that everyone was making fun of it...? I was more confused why is it taken as a joke? It is either that the people on Insta are the wrong people to talk to about it, or I am just...the weird one? I hope not.

For the past three years we have been working on a sci-fi space opera series called Cosmos. This will be a three season long, CGI series, taking place several hundred years in the future with robots, aliens, and good old science. It is Star Trek meets I, Robot, told my Neil deGrasse Tyson. We have a good portion of the story sketched out now, and we are about to start working on the scripts. However, we would like more science and less fiction in our story (more The Martian, less Star Wars), so we need all of the futuristic sci-fi elements to have a very good foundation in real-life physics, no mumbo jumbo. For that reason, we need knowledgeable science consultants, who a…

To choose random walk on a graph, it seems natural to to assume that the walker jumps using each possible edge with the same probability (1/degree) - such GRW (generic random walk) maximizes entropy locally (for each step). Discretizing continuous space and taking infinitesimal limit we get various used diffusion models. However, looking at mean entropy production: averaged over stationary probability distribution of nodes, its maximization leads to usually a bit different MERW: https://en.wikipedia.org/wiki/Maximal_entropy_random_walk It brings a crucial question which philosophy should we choose for various applications - I would like to discuss. GRW …

How did Avogadro 'actually' derive his law stating "equal volumes of gases under similar conditions of temperature and pressure contain same number of molecules" ? I am a 10th grader so I would appreciate a lucid and intuitive explain if the derivation involves higher concepts of science.

Does cardboard reflect or absorb UV present in indirect sunlight?

This thread was inspired by comments from Markus Hanke about how important 'local' is. So if some effect is either local or non local what does these mean ? For instance how big a region does a local effect affect ? Does it make any difference whether we are talking galaxy sized, or microbe sized ? Is there any relationship between the size of the region and the effect? Similarly if something is not local (non-local ?) what is then affected ? I have in mind that a non local effect may be distributed without affecting the whole universe. And also the difference between extrinsic and intrinsic properties.

For a few decades they have unsuccessfully searched for proton decay in room temperature water, what seems interpreted as disproof of this possibility ... but is it really? The same way we could "disprove" nuclear fusion as it practically doesn't happen in room temperature water ... but happens in extreme conditions. So maybe it didn't disprove baryon number violation, only it needs extreme conditions e.g. to get into some higher energy state before decay? Baryon number violation is hypothesized in baryogenesis, Hawking radiation - which need quite extreme conditions. It is required in many models like supersymmetric, or now popular sphaleron. How can …

I keep hearing conflicting stories about what clothing is most effective at beating the heat. Some say white clothing is best to reflect the heat away. Others say dark clothing is best to absorb heat from the body and then radiate it elsewhere. (I would assume white during the day, dark at night?) Some say loose clothing is best to allow convection currents under the clothes, others say tighter clothing is best to radiate heat. Some say it's more effective to wear less, others to wear more. (It's possible the former's just an excuse by narcissists to show as much skin as possible, but it's possible the latter's an excuse by puritans to put modesty over health.) …

Dear scienceforums.net, So i've tried indulging in doing simple python simulations of gravitational phenomenon and have been thinking about simulating a form of gravitation given by an inhomogeneous wave equation version of gauss law of gravity. This is for a personal interest of mine and not because I think such a representation of gravitation would actually be more successful in matching observations. Though i'm fairly curious as to what you would expect in terms of galactic rotation curves with such a simple time retarded potential theory of gravitation. The equation is given below, \[ \nabla^{2} \phi - \frac{1}{ c^{2} } \frac{\partial^{2} \phi }{ \partia…

Why we are using to realize an IN function with diodes reversed biad diodes?I read in a book that if the present concentration of electrons is bigger than the equilibrium concentration n0(n>n0) the recombinations are bigger than the generations.I do not understand this well,generations are when electrons from the valence band are getting in the conduction band,that means in this case we have more electrons in the atom,recombination is the opposite when electrons are making pairs with holes,so some kind of neutrality,then how recombinations are bigger then generations when n>n0,concluding from my opinion it should be oposite G>R?

Time/CPT symmetry is at heart of many models of physics, like unitary evolution in quantum mechanics, or Lagrangian formalism we use from classical mechanics, electromagnetism, up to general relativity and quantum field theories. In theory we should be able to decompose any scenario (history of the Universe?) into ensemble of Feynman diagrams, apply CPT symmetry to all of them, getting CPT analogue of entire scenario (?) There are many QM-based experiments which kind of use time symmetry (?), for example (slides with links) : Wheeler experiment, delayed choice quantum eraser (DCQE), “asking photons where they have been”, “photonic quantum routers”, Shor algorithm…

Hey everyone, thank you so much for your time. I'm not a physicists by any means although looking to eventually become one possibly in the future since I love science in general. I'm really new to the forums so I hope this is the correct place for this thread! Anyways, to the topic at hand. One of my family members has run down a rabbit hole of conspiracy theories and pseudoscience and does not believe gravity exists. His evidence for such an outlandish claim is a blog by a user called Zetetic Zen. Which states, "gravity is incoherent dielectric centripetal acceleration towards a null-point of counter-spatial inertia. Essentially a hybrid field modality and byproduct…

Here's a question, and my doubt is at the end of the question. I have been struggling with this doubt for quite long and have been receiving mixed opinions. A cell of emf 12 v supplies a current of 400 mA to an appliance. After some time the current reduces to 320 mA and the appliance stops working. Find the resistance of the appliance, the terminal voltage of the battery when the appliance stops working, and the internal resistance of the cell. In my book, the answer to this ques is given as follows: 1. Given, emf = 12 volt, I = 0.4 A Therefore Resistance of the appliance R = emf/ I = 12/0.4 …

A block of 8 kg slides upward through a ramp (without friction) until it goes to rest. ¿What would be the maximum height achieved if the block had an initial velocity is 12 m/s ? I´ve tried to solve it in different ways (Newton´s Second Law, Kinematics equations, etc) but I always get stuck. I´ve arrived to the conclusion that the problem is missing key information about the angle that the ramp forms with respect to the horizontal. Help!

It s said "Dark Matter" occupies about 90% of the Universe. If it was dark we would see quite nothing from the Universe in telescopes. We wouldn't see stars nor galaxies. Actually it should be "Transparent Matter"!

Would passing only ultraviolet light trough a prism onto a 'fluorescent' painted target show if it is of the A, B, C type by the projected angle/deflection?

So when Day After Tomorrow came out, a lot of people were saying online that a temperature decrease would, per the ideal gas law, decrease pressure, and that the movie failed to portray the effects of this drawing air out of enclosed surfaces. This summer after noticing the office's alcohol based sanitizer containers dripping from overpressurization the topic has come to mind again. However, pressure is also proportional to the weight of the air above a given surface. So if the surface area of Earth remains the same, would that not mean the average pressure has to remain the same? Would therefore the volume of the atmosphere contract? (I would assume thermal e…

I am investigating the relation between potential energy and field energy. I think electric and magnetic fields might be simplest to consider. Imagine a simple system of two small charged particles (not elementary particles) separated some distance apart. - we define that the potential energy of this system is U0. - we compute that the energy stored in the electric field is: E0 (note: we computed E0 by integrating the energy density formula for the electric field over the whole space. No need to consider our particles as point charges - say they contain uniformly distributed finite amount of charge in a small finite volume.) We slowly separ…

I would like to understand better how atomic orbitals behave in (magnetic) fields... After reading about Zeeman effect, I understand that electrons bound in an atom might shift their energies when placed in magnetic field. I ask if this energy shift is also associated with some change in the shape of their orbitals? (I guess, this is equivalent to asking if the probability density function changes). I would expect that orbitals that have some angular momentum (and magnetic moment) do change their shape. I read that atoms near a magnetar star could look needle-shaped... But I don't see how would an orbital with zero angular momentum (and zero magnetic moment) cha…

If all the molecules at the same height in a container feel the same pressure then how does it remain true if the shape of the container is changed? Where are the vertical reaction vectors coming from on the right side, given that the container is a single rigid body and is thus not being pushed down onto the liquid molecules by gravity?

Hi everybody, I would like to share with you a crewed interstellar spacecraft which I have designed and called Solar One. It employs a combination of 3 propulsion methods: nuclear fusion, beam-powered propulsion , and photon propulsion. Basically, several compact fusion reactors power a laser system that propels a huge light sail. Physicist Robert Forward already proposed in 1983 to use a 26-TW laser system to propel a 100-km light sail, a fresnel lens to focus the beam of the laser, and decelerate the spacecraft with a secondary light sail. I propose something a bit different, which is to use to use for example a 60 TW-laser to propel a 5-km ligh…