# What is Depth: Definition and 362 Discussions

A depth charge is an anti-submarine warfare (ASW) weapon. It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive hydraulic shock. Most depth charges use high explosive charges and a fuze set to detonate the charge, typically at a specific depth. Depth charges can be dropped by ships, patrol aircraft, and helicopters.
Depth charges were developed during World War I, and were one of the first effective methods of attacking a submarine underwater. They were widely used in World War I and World War II. They remained part of the anti-submarine arsenals of many navies during the Cold War. Depth charges have now largely been replaced by anti-submarine homing torpedoes.

A depth charge fitted with a nuclear warhead is also known as a "nuclear depth bomb". These were designed to be dropped from a patrol plane or deployed by an anti-submarine missile from a surface ship, or another submarine, located a safe distance away. By the late 1990s all nuclear anti-submarine weapons had been withdrawn from service by the United States, the United Kingdom, France, Russia and China. They have been replaced by conventional weapons whose accuracy and range had improved greatly as ASW technology improved.

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1. ### A Moire potential depth from continuum model

Dear All, I am trying to calculate the moire potential depth of transition metal dichalcogenide system. I have attached supporting material obtained from one of the thesis. Here they have describe the continuum model hamiltonian for TMDs homobilayer. My question is how to obtain the moire...
2. ### Depth dose calculation in Geant4

I want to calculate depth dose in Geant4. I will use the TestEm11 example for this. How can I convert the output values to Gy?
3. ### Calculating Radius & Water Depth of a Spherical Bowl

The water level in a spherical bowl has a diameter of 30 cm. If the horizontal diameter of the bowl is 10 cm below the water level, calculate the radius of the bowl and the depth of the water in the bowl. I managed to draw a diagram below: In my drawing, I am seeing the sphere ABCD as the...
4. ### Mathematica Loop with variable nesting depth and variable count at each level

In Mathematica, how can we have "M" levels of nested loops, with each loop (level) going from 1 to Counts=##\{N_1, N_2, ... N_M\}## respectively, where the value of M and the elements of Counts are computed beforehand?
5. ### Finite potential well problem penetration depth

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.
6. ### Apparent depth of an object underwater

I would know how to solve this problem if the person had been standing pratically above of the object underwater by using Snell's law and the approximation ##\sin(\theta)\approx\tan(\theta)## fopr ##\theta## small, but in this case I don't see how to find the angles ##\theta_1## and ##\theta_2##...

8. ### A Penetration depth of a ion beam coupled with an EM wave

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...
9. ### I Hydrostatics: Pascal's principle and ocean depth

Hello everyone! I've been learning about hydrostatics and one thing that I've heard is that the pressure is the same throughout confined incompressible fluids, this is one of the reasons hydraulics work, because when you have the same pressure per square meter, you can change the mechanical...
10. ### B Apparent Depth - What remains constant?

Hello! Just now I began to question myself about something I learned many years ago. When we are outside of a pool and see a coin in the floor of the pool (underwater) we think that the coin has an apparent depth that is smaller than the real depth. To calculate this we extrapolate the light...

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12. ### Geometrical optics: using Snell's law, find the depth of the pool

α=30°; l=0.5 m; n1=1; n2=1.33 α+β=90°, so β=90°-30°=60°. Using Snell's law: sinβ/sinγ = n2/n1 sinγ≈0.651 γ≈41°. β=γ+θ (vertical angles) θ=60°-41°=19° tan(θ+β)=l/h h=l/tan(θ+γ) h=0.5/(tan(19+41))≈0.289 m
13. ### MHB Solving UnboundLocalError for Python Iterative Deepening Depth First Search

This code is for iterative deepening depth first search in python. # Python dictionary to act as an adjacency list graph = { '7' : ['19','21', '14'], '19': ['1', '12', '31'], '21': [], '14': ['23', '6'], '1' : [], '12': [], '31': [], '23': [], '6' : [] } visited=[] goal='31'...
14. ### Comp Sci Exception has occurred: UnboundLocalError local variable 'depth' refer

This code is for iterative deepening depth first search in python. # Python dictionary to act as an adjacency list graph = { '7' : ['19','21', '14'], '19': ['1', '12', '31'], '21': [], '14': ['23', '6'], '1' : [], '12': [], '31': [], '23': [], '6' : [] } visited=[] goal='31'...
15. ### MHB How to check if search problem has no solution in depth limit search?

Depth-limited search can be terminated with two Conditions of failure: Standard Failure: it indicates that the problem does not have any solutions. Cutoff Failure Value: It defines no solution for the problem within a given depth limit...
16. ### How to check if search problem has no solution in depth limit search?

Summary:: standard failure in depth limit search. Depth-limited search can be terminated with two Conditions of failure: Standard Failure: it indicates that the problem does not have any solutions. Cutoff Failure Value: It defines no solution for the problem within a given depth limit...
17. ### Buoyancy: Will the Object float or sink or remain at a depth?

My answer was coming b but it's given wrong in my textbook. Because if a body is submerged completely in a liquid then buoyancy Force = mg So if the net force is Zero then shouldn't the body remain there? Plz can someone tell where did i went wrong? Also can a body float inside a liquid Because...
18. ### B Using Compton Scattering to Determine Interaction Depth in Materials

If I have a material with some thickness , say 0.5 meters and I have an incoming gamma photon that undergoes Compton scattering. The gamma ray loses some energy and is shifted in angle with respect to it's original trajectory and leaves the material. The electron gaining KE in the interaction is...
19. ### TV antenna dish: depth, f/D, or focal distance

I am covering parabolic antennas with a school student in elementary physics, and I was looking for the specs of the (offset) antenna on her family's roof in order to calculate things like focal distance. She sent me a photo (she is on another continent), I found the brand specs, which lists it...
20. ### Plug the Closed Ends of a Pipe at Depth and Bring it to the Surface

Hi Guys - I have very simple question but I cannot get my head around. Say if we cut pipeline into one section (12m) then close each cut end with temporary plugs Water depth is 100m. Before the cut there is seawater inside the pipeline. Now I understand there is no differentiated pressure...
21. ### Skin depth of multilayered (2-layer) wire

Homework Statement:: Not a specific question, more just a conceptual clarification for a project. But generally: What is an equation for the effective skin depth of a multilayered (in this case only 2 layers) wire, as a function of the resistivities and relative permeabilities of both of the...
22. ### I Is London depth in superconductors analogous to skin depth?

London penetration depth that's defined for superconductors has a similar equation to skin depth in conductors derived from maxwell's equations. Are they equivalent?
23. ### Free fall question -- Dropping a pebble into a well to figure out the depth

t=7s v=340m/s v=v0-gt 340=v0-9.8x7 v0=408.6 d=d0+v0t-0.5gt^2 d=0+408.6x7-0.5x0.8x7^2 d=2620.1m this is what I've done but apparently is incorrect, not sure why or what the proper method is
24. ### Concept of Hidrostatic Pressure in Random Shaped Vessel

Hello Everyone! this question is using Indonesian language, i have translated the question at "Homework Statement". The container is filled by water (in Indonesian, "Air" means "Water") i know the the pressure at point X, Y and Z depends on their corresponding depth. my best answer is : Pz >...
25. ### What is the definition of Unit Optical Depth?

$$\chi = n \sigma$$ Where Chi is the Opacity, n is the number density of absorbers (constant), and $\sigma$ is the cross section(given). We define the optical depth is just the number of photon mean-free paths in a given physical step, i.e. if we consider a...
26. ### A sudden change in the depth of delta function potential well

is it correct that the continuum states will be free particle states? and the probability will be |< Ψf | ΨB>|^2 . Where Ψf is the wave function for free particle and ΨB is the wave function for the bound state when the depth is B.
27. ### A EM Penetration Depth Into the Ground

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...
28. ### Is the skin depth of tarnished silver any different than untarnished?

That's it, just the question. I am figuring that the tarnish is an irrelevance as it does not participate either magnetically or electrically, so any RF current passing through the [still metallic] silver top layer, albeit with tarnish over the top, will pass through the same thickness of...
29. ### Electron moving to the face of plate from depth d

I don't really understand the question. I don't understand the wording. We know the plate has a thickness L = 0.50cm. If the charge is coming from the battery wouldn't the electrons have to move the entire distance to reach the face of the plate? Because they have to move all the way from the...
30. ### Depth to which the sphere is submerged

I draw a sketch of the diagram to the right. The body has a radius of ##r_B = 0.2## m. The volume of the body is given by ##V_B = \frac{4}{3}\times \pi \times 0.2^3 = 0.034\;\text{m}^3##. The mass of the body : ##w_B = \rho_B V_B = 400\times 0.034 = 13.37\,\text{kg}##. Hence the mass of the...
31. ### Explaining Pressure & Depth Relationships in Fluids Using Halliday & Resnick

Homework Statement:: Not a homework problem. I need a conceptual explanation. Relevant Equations:: ##p_2 = p_1 + \rho g(y_1 - y_2)## (1) ## p = p_0 + \rho gh## (2) When deriving equation (1) we use the example of a submerged cylinder in static equilibrium with its top at position ##y_1## and...
32. ### Thermal penetration depth experiment

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...
33. ### MHB Engineering Mechanics: depth of crater

The depth of the crater of the Taal volcano was calculated in the following manner: From a helicopter flying vertically upward at 6m/s. A small bomb was released at the instant the helicopter was 20m above the crater surface. The sound of explosion was heard 9sec later. If the speed of sound is...
34. ### Finding Characteristic Depth of Strip Foundation

hello everyone! i have some problem in solution of this problem should i transfert the vertical stree to the horizontal stress and solve it ? problem : The equivalent static stiffness of the soil as an infinite elastic half-space under an infinite strip foundation is given in the vertical...
35. ### Optical depth using Bremsstahlung emission coefficient

Equations I think may be relevant:

37. ### What is the maximum depth to which a P-wave ray can travel?

I've created an excel spreadsheet with the given model in addition to calculating radius of the layer by subtracting depth from 6371. I've calculated Zf. I've also found what I think is vs by doing alpha * (radius column/6371), but that could be wrong. I know I need to find where 20/6371 =...
38. ### Engineering Power Loss Definition in a Damped Wave Equation (Skin Depth Problem}

Hi, So the main question is: How to deal with power loss in E-M waves numerically when we are given power loss in dB's? The context is that we are dealing with the damped wave equation: \nabla ^ 2 \vec E = \mu \sigma \frac{\partial \vec E}{\partial t} + \mu \epsilon \frac{\partial ^ 2 \vec...
39. ### A Mode Field Diameter and Penetration depth of the Evanescent field

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...
40. ### Is cavitation worse at depth? (Fluid pressure and Vapor pressure boiling)

I am wondering about the impact of the hydro static pressure of a fluid on its boiling point. The simplest real world example scenario I can think of is the rate/onset of cavitation at a large depth vs a shallow depth. As we increase the submarine propellor speed to a speed where the adjacent...
41. ### How to calculate Carrier Concentration vs. Depth from a CV measurement?

I'm trying to obtain the free carrier concentration vs depth profile from the CV (capacitance-voltage) measurements of a normally-on HEMT with the expressions used for a Schottky barrier, but I´'m confused about how to extract the values for depth. I found in textbooks and articles that the...
42. ### Investigating Motion of Rockets & Satellites: Advanced Mechanics Depth Study

Homework Statement: Hi, I just got my first year 12 assignment which is a depth study of advanced mechanics. I had one idea of investigating the motion of rockets and satellites. I could even do something with circular motion or projectile motion, taking air resistance into consideration. I...
43. ### How do we get data about the Earth's crust?

In this video about digging hole into Earth's crust it is said that humans have only reached 12 km depth(Kola Superdeep Borehole). Then how are we able to know the composition of Earth's crust, density of innermost core, physical state of the matter. Where are we getting our data from And how...
44. ### Depth of NPT Holes: How to Fully Screw in Fittings Roy's Q&A

Hello everybody! I've notice that when using NPT fittings, the female fittings usually doesn't take all of the male threads: This has never bothered me since these are commercial fittings and the engineers who designed them know what they are doing. But now, I need to make NPT holes in a...
45. ### Year 11 Physics depth study (Waves and thermodynamics)

I don't know how to make the practical or what practical I can conduct that would test the question we have been given.
46. ### Depth effect in mirror reflections

A simple question but the answer is not apparent to me. I just know so little about optics. When I look at an object, I gather an impression of depth because my eyes have to adjust to the object's distance from me. I assume this is due to the angle of the light from the object - light coming...
47. ### Critical angle: find the depth of the fish looking up

Homework Statement A fish floats in water with its eye at the centre of an opaque walled full tank of water of circular cross section. When the fish look upwards, it can see a fish-eye view of the surrounding scene i.e. it is able to view the hemisphere of the scene above the water surface, and...
48. ### Find the maximum safe depth of a submarine

Homework Statement An ocean-going research submarine has a 40.0 cm -diameter window 9.00 cm thick. The manufacturer says the window can withstand forces up to 1.20×106 N . What is the submarine's maximum safe depth? The pressure inside the submarine is maintained at 1.0 atm. ρseawater = 1030...
49. ### Penetration depth and step potential

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...
50. C

### I What is meant by "low frequencies"? (EM skin depth question)

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...