Depth Definition and 363 Threads

I'm studying conductors, where complex wave number ##K=k+iα## and complex index of refraction ##N=n+iκ## is introduced. My textbook(Fowles Optics) says that for "very low frequencies", skin depth δ is equal to ##δ=\frac{1}{α}=\sqrt{\frac{λ_0}{cπσμ_0}}##. What is "very low frequency"? How much...

I was just wondering if there are any resources on mathematics and physics that explain the origins of the concepts. I am not currently in college right now but I absolutely love physics and quantum mechanics. I am trying to understand the nature of reality because it is so fascinating. I'm...

I observed a photograph taken with my telephone, and it has depth of field. foreground blurring of an metal grid mesh. yet some objects in the background are visible troughout the total blur of the mesh. marked with green circles. the depth of field or focal blur, almost makes the metal mesh...

I know the concept of apparent depth as such: It is the depth at which an object is seen when viewed from a different medium. But i want to know what happens when two refracting surfaces are kept one after the other. In the given diagram let the object be placed at the bottom of the vessel...

Homework Statement A city with 30,000 residents lies next a lake which is their only source of water. The average family of four in this city uses 1100 liters of water per day. Neglecting rain and evaporation, how much depth would the lake lose per year if it covered 40 square kilometers...

I have not posted for a while,but something has been bugging me. I would like help understanding that if mass makes a dent in the fabric of space, does it mean celestial bodies are sitting at different depths in the fabric, and does that mean the less mass in an object you are then more likely...

It is based on the value of the edge coefficient I obtained, for Germanium at the wavelength of 1550 nm has a value of 459.54 / cm and GaAs at wavelength 885.6 nm has a value of 239.78 / cm. If based on the theory of absorption depth (1 / alpha), then the optimal thickness of GaAs is thicker...

I'd like to rig up a glass pressure vessel to see if I could demonstrate crush depth and stuff like that. I was sort of picturing a large small-necked glass jug (think water cooler jug) filled with water and attached to a compressor (or maybe even bike pump?). Styrofoam objects would be...

Hello, Using surface energy dependence on surface orientation it is possible to predict equilibrium crystal shape by applying Wulff construction. But I faced the problem when the surface energy depends not only on the surface orientation but also on the surface depth or surface termination and...

Hello! (Wave) I am looking at the following exercise (pg. 92, ex. 11.1 , book:Gems of Theoretical Computer Science by Uwe Schöning ) : Why can all boolean functions on $n$ variables be computed by a circuit with only 2 levels (a depth 2 circuit) ? What is the size ( number of gates ) of such a...

Hi, so someone probably has already asked this, but does temperature increase or decrease with depth in a fluid? I thought it would decrease since it has more pressure but it is probably wrong, or doesn't make sense. I was confused because the ocean gets colder the deeper you go, but then does...

Homework Statement A 9 cm square wooden post (density=420kg/m3) is 1.3m long and floats in sweater (density=1029 kg/m3. How deep is the post submerged in the water? The picture shows a 9cm x 9cm cross section of the post. Homework Equations Fb=density of liquid x volume of liquid submerged x...

Homework Statement (a) A rectangular gasoline tank can hold 39.0 kg of gasoline when full. What is the depth of the tank if it is 0.450 m wide by 0.900 m long? m (b) What is the volume of the tank? (It is suitable for a passenger car.) gal Homework Equations Density of gas=719.7=mass/volume...

I'm trying to find the impact or penetration depth of a projectile in the (reasonably) most realistic way possible. I assume this has many factors including velocity, the densities of both materials, shapes of both materials, the medium of which the projectile travels through, gravity, etc...

I'm writing a real time 3D physics simulator that simulate bullet ballistics. Can I use the air drag formula that factors in drag coeficient and outputs drag force to calculate how deep a bullet will penetrate a target material? Say I substitute air pressure with target material density. And...

How deep can a submarine volcanic vent be and still generate a significant pumice raft ? Sadly, Wiki is a stub, and most of the relevant literature is pay-walled. As I understand it, deep vents may generate a lot of pumice, but it never reaches the surface, just stays on the vent's flanks...

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...

So we are studying optics in school this semster, Very interseting topic I say but I just have a couple of question I want to ask. In concave and convex mirror, we study spherical ones where F = R/2. I was able to prove this and that it is only an approximation when ## R >> h_o ## or ## h_0##...

Homework Statement The uniform 5 m-long round wooden rod (ρ = 800 kg/m3 ) is tied to the bottom by a string with length 1 m. Determine the inclination angle θ if the water level is 3.5 m. What if the water level is 7m? Homework Equations Fb = ρgV The Attempt at a Solution So I'm really...

Homework Statement Here's the velocity profile of the water across the depth . I don't understand why The max velocity occur at the top surface[/B]Homework EquationsThe Attempt at a Solution Is it because the friction on the top surface of water only comes from the below , whereas for the...

Homework Statement Homework Equations dp/dz=-ρg p=ρgh The Attempt at a Solution I've found the density at depth 3m using ρ=ρ0+kh, which gave me 1060kgm-3. I then put this value into ρgh to get 31195.8Pa which seems to be ≈+1000 off the answer. What is the correct mathematical way of...

https://scontent-vie1-1.xx.fbcdn.net/v/t34.0-12/14955857_1113106435476531_5016282393940245289_n.jpg?oh=c2e50935ccd57a0863d5f00c5b56653a&oe=5821DD35 Shot point A and B are located at a 225m spread of 16 geophones. Using the data in the attachment, Find 1. The Velocities, V1and V2 2. The Dip()...

Hi, I have a waterproof smartphone with sensors like barometer, gyro, accelerometer, microphone). I want to do an app that 1) detects that the phone is underwater: I though in using some reading from touch panel as water is electro conductive and it may provide me some reading to indicate...

Is there a connection between consciousness and emotions? Imagine humans are a class 5 conscious animal and have the most complex emotions. An elephant or a gorilla may be a class 4 conscious animal, a dog a class 3 etc. I would certainly think a gorilla possesses a deeper consciousness than a...

Homework Statement Assume that the pressure p and the specific volume v of the atmosphere are related according to the equation ## pv^{1.4} =2.3*10^3 ## where p is in ## N/m^2 ## and v is in ##m^3/kg ##. The acceleration due to gravity is constant at 9.81 ##m/sec^2## .What is the depth...

Homework Statement refractive index = 1.33 (water) real depth = 10m Homework Equations refractive index = real depth divided by apparent depth The Attempt at a Solution I'm going to call apparent depth X 1.33 = 10/x So I multiply 10/x by 10 so that i have x and 1.33 x 10 is 13.3... that's...

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...

hi, nowadays I try to get involved electromagnetic waves equations, and I came across that $$ \nabla $$ is treated like $$ ik $$ and $$ \frac {\partial } {\partial t} $$ is treated like $$ -iw $$ And if you look at the part painted with orange in my attachment, afterwards you can see that $$...

Hi. A student wishes to test gravitational time dilation near a black hole within her lifetime, so she travels to a location where a black hole is said to reside and parks her ship at distance where she is not affected by the hole's time dilation effects. She then fires a tethered capsule...

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 (?)...

Homework Statement The light beam travels from air into water,the angle of incidence is 60 degress. The bent beam creates point F on the bottom of eater tank.If we imagine extension of incident beam inside the water, we obtain point B on the bottom of water tank. The distance between F and B is...

Hi, can someone please explain to me where this equation derives from and how it works? d'=d(n2/n1) where d'=the apparent depth of the object, d=the actual depth, n1= the index of refraction of the medium in which the refracted light travels, and n1= the index of refraction of the medium in...

So if you were scuba diving and your depth gauge broke, could you create a system where you exhale some air and record the time it took to reach the surface. If so, what would they equation look like?

I'm doing a question relating to the pressure inside on object submerged in water. Here is the question: A tube, height 1.2m, is submerged vertically in the ocean where the waters density is 10^3 kg/m^3. A diver initially holds the tube vertically directly on top of the water. He then dives to...

Homework Statement Comment how the energy and wave functions of the electron would change in the case of a finite dept quantum well with the same width. Homework EquationsThe Attempt at a Solution I feel completely clueless as how to approach! :( * The full question can be found in the...

You know the proofs for finding the apparent depth of a swimming pool, or object submerged in one? Well, it always assumes the object is directly above the original object. Does anyone know where the assumption comes from? (see below)

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 =...

After passing the thermocline, in which water temperature decreases rapidly over short distances, temperature falls into a sort of constant-looking decline. However, looking at the graph, it looks almost asymptotic. I've not been able to find a chart measuring water depths below 10,000m, so I'm...

Hey guys, many might find my question stupid, but I could really really use an answer. Imagine a 1 cubic meter cylinder that weighs 1.2 metric tons. It displaces more water than its volume, so it will sink. For the sake of simplicity, let's imagine there's no drag and it's hydrodynamic. As it...

This is a slight twist because I'm not looking to establish a colony under water, however my interest is still with ocean exploration. Allow me to ask the question: Could we design an unmanned submersible exploration machine that can dive to the depths of our deepest capabilities with a sub...

It should be noted that this is not homework but rather practice for an exam. Is this the place I should be asking these types of questions? Homework Statement An apple is held completely submerged just below the surface of the water in a container. The apple is then moved to a deeper point in...

Homework Statement As a submarine dives, the pressure on its hull.. a. remains constant b. increases c. depends on the decrease in volume of the submarine d . decreases e. depends on the thickeness of the walls of the submarine Homework Equations P = F / A The Attempt at a Solution Not a...

If I use 10mm (thickness) of a metal for the sides of a Faraday cage, with a 5mm skin depth at the frequency to be shielded, & increase the v/m of the EM wave to be blocked gradually, will there be a stage where the skin depth will increase to 6mm, or is 5mm the maximum limit?

Hello everyone, I am working thru some of the mathematics of geo-exchange systems (semi passive heating and cooling systems for homes) and I'm starting with a very simple model: The ground is modeled as a perfectly insulated rod (perfectly insulated because of symmetry, there is no heat flux in...

Homework Statement Astronomers discover a new transiting planet named Jakku. The parent star, Abrams, is known to have a radius equal to ½ that of the Sun’s. a) The transit depth of Jakku is 757 parts per million (757 x 10-6). How large is the planet? Convert your answer into units of Earth...

Homework Statement [/B] Homework Equations Resolution lateral = 1.2λ f/dThe Attempt at a Solution R lens 1 = 1.2(750nm) (1/5) = 180nm R lens 2 = 1.2(750nm) (3/5) = 540nm However these are laterial resolutions. If it possible to find the depth resolution from this or am I missing a formula...

Homework Statement A stone is dropped from rest into a well. Th sound of the splash is heard exactly 2.00 s later. Find the depth of the well if the air temperature is 10.0 degrees Celsius. Homework Equations How does the speed of sound play a role in this? How can I find the depth? The...

The Wiki article on the CMB says that recombination lasted for around 115,000 years, from 372,000 years after the BB (when all baryonic matter was in the form of ions) until around 487,000 years after the BB when all electrons had bonded to nuclei. So Thomson scattering gradually decreased from...

Homework Statement a fish at a depth d underwater.Takes the index of refraction of water as 4/3 show that when the fish is viewed at an angle of refraction θ , the apparent depth z of the fish is z = (3d cosθ )/ √ (7 + 9 cos2 θ) Homework Equations snell's law n1 x sin θ1 = n2 x sin θ2 The...

Do physics graduate programs have any preference of working with a single professor for several semesters or working with several different professors each for just a semester or two? Is it disadvantageous to stay with one professor for your entire undergraduate career?