Penetration Definition and 88 Threads

Hey everyone, Im doing this research and reading this http://science.hq.nasa.gov/kids/imagers/ems/gamma.html" it had a diagram of the depth of penetration of different wavelengths into the eaths atmosphere... my question is, How come x-rays penetrate deeper than visible light - what is the...

So I'm doing a presentation soon discussing the horribly inaccurate physics of the movie "The Core", and in particular how they were able to maintain radio contact to people on the Earth's surface from within the center of Earth. This is obviously simply not possible as radio waves do not...

An electron having total energy E=4.46 eV approaches a rectangular energy barrier with U=5.02 eV and L=949 pm. Calculate this probability, which is the transmission coefficient. I thought this would be an easy one, given that T=e-2GL and G=\sqrt{\frac{2m(U-E)}{H}} where H is the...

If you held frequency constant, and changed the amplitude of EM waves coming from a source, then would the distance into a material the EM waves would penetrate change?

Approximately how far will a signal penetrate a fresh water pool from the surface to a swimmer assuming current Wi-Fi standards? With at least 6-8" of water penetration I would purchase an iPod Touch and listen to streaming radio while doing laps. Thanks, Mark

When an EM wave has a higher frequency, it is able to penetrate materials more easily. However, why does a microwave able to penetrate haze while visible light can't? Why visible light is able to enter our atmosphere while those of gamma can't?

Hi, I'm new to physics forums and I was wondering how to calculate the force required to penetrate objects of varying densities, for example an arrow shot at a plank of wood with a density of approximately 1.2 x 10^3 kg/m^3. Let's assume the arrowhead and the plank are perpendicular at the site...

I couldn't sleep the other night because I was thinking about photons and their ability to penetrate materials. It can be argued that humans are photon detectors. This is true in more than just the sense of visible light because photons don't just enter our pupils. As an example, our bodies can...

hi guys. i have the london penetration depth defined as \lambda_l = \sqrt{\frac{m^{**}}{4\pi n_{s} e^{2}}}. i'm trying to figure out the dimensionality of it...surely it must be a length, but i get [(Kg)(m^{3})(A^{-1}s^{-1})]^{0.5} in SI units. am i doing something wrong? cheers.

Homework Statement Calculate minimum thickness of concrete wall of radiation room (2X2X2) such that radiographer doesn't exceed dose limit. Use info below. X ray reading surface of patient (50 cm from source) = exposure= 4.29 X 10^{}-4 effective energy of x ray beam = 40 kev 40% of x rays...

Hi everyone. What is the difference between the London penetration depth and the Josephson penetration depth? Both of them have to do with the penetration of a magnetic field into the superconductor as far as I can see...

Neutrinos can pass through solid objects like the Earth easily, and a light-year of lead would only stop half of them from passing through. What about something very dense like a white drawf or neutron star? How readily can neutrinos penetrate that? What % flux reduction would be achievable...

why does the increase of sound frequency will decrease the penetration depth? how can this related to diffraction of sound?? Is it because they can be easily reflected?? need answer desperately, thx

penetration depth??! How would I find the penetration depth of a staple shot into a material by a staple gun. It doesn't have to be specific to a staple. Material I am concerned with is pvc. Even a general approach is fine. I know the force opposing the staple going in is the friction of the...

Penetration depth? How would I find the penetration depth of a staple shot into a material by a staple gun. It doesn't have to be specific to a staple. Material I am concerned with is pvc. Even a general approach is fine. I know the force opposing the staple going in is the friction of...

Right, so I've just created my Franken-Equation and it hungers for brains, as well as acceptance. Unfortunately for my monster, he was created by a man with only rudimentary knowledge of the nervous system and a budget consisting of earnings from his less than successful homemade mosquito...

Why does penetration increase with decrease in wavelength?

I've been wondering about this for quite some time, and I was hoping I'd get some answers here. Well, here goes: 2 projectiles (bullets) enter the same homogeneous medium (let's say concrete) at a 0 degree angle. Both projectiles have identical impact velocities, however, "Projectile 2" has a...

Is kinetic energy or momentum a better indicator of bullet penetration?

I'm trying to disprove the movie Wanted for a less than obvious reason. In the final scene a .45 ACP round travels through 11 human heads. I was curious of how I could mathematically disprove this being possible. Would I use the energy of the bullet or the force? and with either, how would I go...

Homework Statement An electron with KE = 8eV is incident on the potential step of height 7eV. What's the probability the electron will be reflected from the step function? Homework Equations The wave equations and their derivatives: \psi_0(x) = A sin(k_0 x) + B cos( k_0 x) \psi_1(x)...

A simple modelling of projectile penetration in a fluid was simplee (drag), but with solids I'm having a little trouble. Would it be too crude an estimation to use the following model? F = \frac{E}{\delta{s}} F = projectile force E = kinetic energy s = depth in steps \tau =...

Can radio waves propagate through the walls of a solid steel (1/2" wall thickness) box that completely encloses the RF transmitter? Do lower frequencies work better? Any insight would be great. I'm a newbie her, so please be gentle.

Hi, I have an FEA model where all my parts are bonded contacts (no contact surfaces). I am trying to fix one end of this model and apply inertial load on the other. However the heavy parts are penetrating into the soft ones. How do I avoid this model penetration? Thanks,

Homework Statement Calculate the de broglie wavelength (DBW) of an electron with kinetic energy 60 GeV. What percentage of an atom's diameter can it penetrate? Homework Equations DBW = h/p p=mv The Attempt at a Solution Basically I have an electron traveling at the...

Homework Statement A 7.00g bullet, when ired from a gun into a 1.00kg block of wood held in a vise, penetrates the block to a depth of 8.00cm. This block of wood is placed on a frictionless horizontal surface, and a second 7.00g bullet is fired from the gun into the block. To what depth will...

If we want to secure an area from beta particles, we could use absorbers, for example aluminum foils. Is it preferable to use one thick aluminum foil or several aluminum foils (with same total density as the first one of course) with free space between them? In other words, does a beta particle...

In Traditional Archery, there is a widely held belief that momentum is the best indicator of an arrow's capacity for penetration. The most important support for this theory comes from this document: The Ashby Report<---Link to document (PDF) This document has never been reviewed or proofed...

Hi all, I'm currently trying to write a simple physics demo with cubes, and am looking for the best way to handle penetration. One method I was looking at is to back-track the collision detection till we find the point of intersection within some limit.. i.e. collision at dt, so we step...

Is it possible that simply getting an outdoor electrical cord wet, it can somehow trip a GFI circuit? I have a pool pump with its own waterproof cord (i.e. not an extension cord) and, as far as I can tell if the cord finds even a couple of feet of itself in a puddle of water, this will trip...

In the giant proximity effect of superconductors, the penetrating supercurrent can be modeled using bosons. During some project work, modeling this phenomena Using vortices, I was thinking, whether the bosons can penetrate the interface of the normal conducting material being modeled by a helix...

Many textbooks derive the relativistic momentum from the penetration depth of a bullet in a resistive media, considering that momentum is proportional with the penetration depth. Do you know a transparent and correct way to the problem?

-------------------------------------------------------------------------------- it is generally accepted that 800 mhz frequencies (longer wavelengths) travel farther and penetrate buildings better than 1900 mhz frequencies (shorter wavelengths) I have looked for hours on the Internet trying...

We have a particle of energy E crossing a potential jump at x=0. for x<=0, V=0, for x>=0 V=V1 We get a wavefunction for x>=0 psi(x) = exp(-iEt/hbar)*exp(-Kx) where K = (2m(V1-E))^0.5/hbar N.b E<V1 so classically we get no transmission we are asked to estimate the penetration distance, and...

Why can just about all frequency/wavelength electromagnetic waves penetrate through physical objects (even if only a thin piece of wood or something) but light cant?

The problem is as follows: A 50-eV electron is trapped between negligible-width capacitors charged to 200V (each with an exit hole). How far does its wave function extend beyond the capacitors? I know the answer is 1.6 x 10^-11 m, but I cannot get to that. Any ideas? -Jason

I have a question to do but I am a bit confused about one thing. It invloves protons penetrating a barrier. The protons ae quoted to have a KE in the units of eV (which i will have to convert to joules in order to work in SI units). However the barriers height is given in volts. I assumed...

Depending on energy, how far will an Electron penetrate a block of acrylic? If you have any clue or where I could begin to formulate the equation thank you.