Penetration Definition and 88 Threads

Imagine you have a proton beam with sufficient speed say Xc to overcome the Coulomb Barrier for the element in use. The beam collides with a cloud of that element with density (rho) and thickness (l). Obviously you wouldn't achieve 100% fusion and if the cloud is dense enough the beam will...

I was quite curious when I noticed that a stake gets progressively harder to drive the deeper it goes into the soil. When I tried looking up ballistics formulas they seemed to disagree and state that there should be a force that should work to penetrate all depths. Does the force increase...

I don't understand where I went wrong, the formula and calculations which I have attached are correct...please do help if anyone can spot the mistake.

A Ion source is a device that allows creating ion beams (e.g. argon ions) and to project them outside the device, for example to be further processed by a particle accelerator, or to irradiate materials or biological tissues etc. Now, suppose the ion beam is coupled with an EM wave, especially...

I read in a book that high frequency electromagnetic waves are more able to penetrate than low ones , so why radio waves can penetrate walls when light cannot?

This problem is in a chapter on momentum in the book basic engineering mechanics explained. Help me Mario

Hello, I'm wondering about the best EM to penetrate deep into ground and sense/detect what's there. The authors here (https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2005JE002528) are recommending P-band with 430 MHz to probe few meters into the ground of Mars; that's about 70-cm...

I doing an experiment that involves thermal penetration of copper. Please advise me where to post if I choose the wrong spot. This experiment is being done with what I have on hand and my ability to work the materials. Materials 2.75 gal pot of water 6qt pressure cooker 100+lb of stripped...

My thought is that they both stem from PRESSURE. Sharp objects have more pressure than blunt objects given the same force and therefore can penetrate softer material better. Some of my associates are suggesting that cutting by stabbing is entirely different than blunt force. But the definition...

Source: fobasics.blogspot.com Source: scirp.org As it is shown in the first pic above that the mode field diameter is defined as the mode field decreases to 1/e (in intensity 1/e^2), if I take the mode field and subtract the core's diameter then I divide it by 2, should I get the penetration...

Hello, I have some questions related to the Penetration Theory proposed by Higbie (1935). I carried out laboratory experiments in a bubble column of 1.3 m filled with water and saturated with oxygen. Air bubbles were rising and the liquid was stagnant (its motion was just due to the rise of...

Explanation: Let's say I have something generating a frequency of 60hz. If I pulse that frequency on and off, 10 times a second, does that amplify the distance that wave will travel through space? Let's assume the medium it is traveling through is consistent for the moment. If the 60hz...

I want a clear formula for clear water (and salty water) penetration by giving only the radio wave frequency . I searched the web , the formulas on the web are so complicated . Are there any simple formula available for that ?

Why do radio waves pass through walls while visible light can't? I guess this has something to do wit the wavelength. What I know is that higher wavelength means higher ability of penetration. So why radio waves penetrate obstacles?

Homework Statement I am trying to figure out the average penetration depth into a finite step potential, similar to this thread: https://www.physicsforums.com/threads/qm-barrier-penetration.104641/ But instead of just estimating the depth as ##\frac{1}{\kappa}##, i would like to calculate it...

Homework Statement Which, of an electron and a proton (of a few Mev), is more likely to penetrate further into matter if they both have: a) The same energy b) The same speed Homework Equations Bethe-Bloch formula. Total stopping power = collision loss + radiation loss (de/dx)t = (de/dx)c +...

Hi pf, I was wondering about a bubble moving with constant velocity in a liquid, and how the motion affects the mass transfer. Since the viscosity of the gas is significantly smaller than the viscosity of the liquid, the condition ## \tau_{gas} = \tau_{liquid} ## tells me that $$ \mu_{gas} (...

This may be an odd question but I am wondering if water speed affects a bullet's ability to penetrate water. Pardon my lack of knowledge, but I am aware that low caliber bullets can penetrate water past 3ft (Thank you Mythbusters). However, the tests they completed were all based around a pool...

Hi all, I'm working through chapter 2 of Michael Tinkham's Introduction to Superconductivity. On page 40, he asserts that the skin-depth for a general complex conductivity is (In Gaussian units) $$\delta = \frac{c}{\sqrt{2\pi\omega\left(|\sigma| + \sigma_2\right)}}$$ where $$\sigma = \sigma_1...

A problem I encounter when microwaving food is that the centre is no penetrated by the microwaves so remains cool and I have to wait for the heat to be conducted through which takes a long time and undermines one of the advantages of microwaving which is the speed of the process. Would it make...

Hello. We are elementary school kids who built a cloud chamber for our science project to test out the effectiveness of different shields against background radiation. We are not sure about something involving beta-particles. Can you help us please? We know low-energy beta particles cannot...

What are the factors that determine the property of wave penetration of bodies? For instance we can listen to fm radio from inside the walls of a room. But visible light is unable to penetrate the walls. Similarly some metals reflect some frequency but absorb some. How atomic orbitals play...

Hi All, Long time absentee from the forums hoping for some direction in my new research. I've been tasked to look into the stages of motion of objects (dropped from various heights), hitting a body of water (of various depths) and eventually hitting the seabed (of various sediment types). I am...

Hi, according to http://www1.lsbu.ac.uk/water/microwave_water.html and other sources the penetration depth of a microwave wave is proportional to the square root of the dielectric constant divided by the dielectric loss. For me it makes sense that as the dielectric loss increases more energy is...

someone asked me about this and I don't know how to answer them. I will attach a couple pictures. They asked me why the light penetrates a certain depth then just disappears instead of gradually fading away. Particularly in the sand bed as seen in the pictures. I've read through this...

If you know the weight of the hammer, and the velocity it hits the nail. What would you need to know about friction forces, etc in order to calculate how far it is driven down into the wood? So assume the hammer weight 0,5kg and it is being swung at 50m/s when it hits the nail. Friction is (?)...

Consider a 5 meter by 5 meter and 1cm thick superconducting plate, now place a very strong neodymium magnet against the underside of the plate.The plate is big enough so that the magnetic field does not go around the plate. Does a magnetic field penetrate the plate or is it blocked completely...

This is a review problem for an upcoming exam. I'm pretty sure a problem very similar to this will be on the exam. And surprise surprise I'm freaken lost. 1. Homework Statement A high index prism is used to launch an evanescence wave at the water/prism interface as shown. A He-Ne laser (λ =...

Asked in 2015 on "Quora," a PhD candidate answered that near-infared wavelengths can penetrate the body more that visible wavelengths, but only by a millimeter or two. She sums up her answer, "So the question: can NIR light penetrate the human body? The first millimeter, yes, through the chest...

A magnetic field doesn't penetrate well into a plasma because it produces currents that counters the field, so to speak. But, before those currents are produced, does the whole of the plasma "feel" the magnetic field? For how long; ns, us or ms? S.A.

Homework Statement : Calculate the penetration depth of an evanescent wave undergoing TIR from glass (n = 1.5) to air interface, such that the amplitute is reduced to 1/e times its original value. Wavelength of the incident light is 5000 angstroms and 60 degrees. First make sure that incident...

G’day physics forum This is a purely hypothetical question and my knowledge of physics is rather limited so I’ve no idea if answering it is even possible however here goes: Imagine a 30cm long timber stick approximately 3mm in diameter that has been placed vertically in an inverted pyramid or...

For a photopolymer, the heuristic goes that longer wavelengths of UV light penetrate deeper than shorter wavelengths of UV light. For example, the UVA spectrum penetrates more deeply into the photopolymer than the UVC spectrum. What is the best way for this to be explained?

For a photopolymer, the heuristic goes that longer wavelengths of UV light penetrate deeper than shorter wavelengths of UV light. For example, the UVA spectrum penetrates more deeply into the photopolymer than the UVC spectrum. What is the best way for this to be explained?

Hi, I want to calculate the penetration depth of some different frequency ultrasound transducers. I know that it depends on the attenuation of the medium but not sure where these types of figures will be hiding. I assume that once the dB lost for the depth is equal to the dB generated, this is...

Homework Statement An unknown element has a nucleus with charge 14.00 e and a radius of about 3.60×10-15 m. How much voltage must be used to accelerate a proton (radius 1.20×10-15 m) so that is has sufficient energy to just penetrate the unknown element? Assume that the potential is that for...

It is known that the penetration depth of photon into a material depends on the energy of the photon, density and atomic number of the material; because the photon energy is normally smaller than the potential against the penetration of photon, which is the potential barrier, so the incident...

So in the infinite well Energy is proportional to 1/L^2, so I'm assuming in the finite well there is some sort of similar relation. So as the L decreases, the energy increases, so the wavelength decreases. Decreasing the wavelength means more energy, so it should penetrate further, but also if...

If F=ma, why does a bullet that's going a constant velocity, have enough force to penetrate an object?

Homework Statement I have a lot of information about 2 different superconductor materials; indium and lead. The indium is pretty much 100% indium with no impurities, and the lead is unknown purity. I have the temperatures and magnetic fields at which they are superconducting and the...

I have been looking for information about the way Radiotherapy works and, needless to say, there is much more involved than just local frying of tissue. I have been told and also read, that the dose received in tissue is not necessarily maximum at the surface. For instance, the dose seems to be...

Hi everybody! Just 2 important notes: I don't study physics and so I'm not sure if this question belongs here (but I don't know where should I put it..); second I'm not english native, so ask me if I did not explain somthing enough. My electronic professor told once in my class, that you...

Is there research or data that measures the penetration of various visible light colors on the human body?

a gas stream has particles of three sizes, 10 micron, 7 micron and 3 micron. The particle density is the same for all three sizes as well as the weight concentration (0.33333). This gas passes through an ESP that obeys Dutch-Anderson equation arranged for the penetration: p=exp^(-Aw/Q) where...

I shoot a bullet of mass m with velocity v against a block of mass M. Find how far the bullet penetrates the block. This problem turned up in my friends examination and I believe it can't be done without the coefficient of friction. Am I right or can this be calculated using conservation of...

So here is the scenario: an adult male 80kg, 6ft tall, slim build free falls into the open ocean feet first, hands locked into the groin. Speed at entry can be 200km/hr. We can assume the water is perfectly stile in reference to the surface tension. and for the body we can estimate some factors...

Homework Statement A bullet with mass and speed v hits a wooden block of mass M that is situated at rest on a frictionless surface. It penetrates the block and gets trapped inside it as a result of a constant retardation force F_{ret} that opposes relative motion between the two objects...

Recently I have come across with the problem of the penetration ability of various kinds of wave and would like seek advice here. 1. Gamma ray has higher energy (higher frequency) as compared with x-ray and therefore gamma ray is considered to have higher penetration ability than x-ray...

Homework Statement Assume that a typical electron in a piece of metallic sodium has energy - E_{0} compared to a free electron, where E_{0} is the 2.7 eV work function of sodium. At what distance beyond the surface of the metal is the electron's probability density 20% of its value at the...

(In SI units) Start with London's 2nd equation in Superconductivity, curl J = 1/(μ*λ²), and Ampere's curl B = μ*j. Then we curl both side curl curl B = μ* curl J and we do the substitution. So curl curl B = 0 - del²B which is the laplacian operator. My question is...how to integrate...