What is Shell: Definition and 783 Discussions

CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system's DOS BIOS (typically residing in IBMBIO.COM or IO.SYS) during boot. CONFIG.SYS was introduced with DOS 2.0.

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  1. PainterGuy

    The shell strikes the water at the same speed?

    Hi Please have a look on the attachment. Do you also agree that the shell strikes the water at the same speed? It seems false to me. The vertical and horizontal motion is independent of each other. When the shell is fired horizontally, it starts descending toward the ground from less height...
  2. P

    Charged sphere and charged conducting shell

    Homework Statement A + q = 5 pC charge is uniformly distributed on a non-conducting sphere of radius a= 5 cm , which is placed in the center of a spherical conducting shell of inner radius b = 10 cm and outer radius c = 12 cm. The outer conducting shell is charged with a -q charge. Determine...
  3. G

    Invisibility like Predator, Ghost in the shell

    What do you think about invisibility suits? One possibility would have lots of mini cameras and pixel that mimic the background of body on the front of the body. But is it a bit realistic to entirely hide a human from different angles and wavelengths, from sensors too? Another option i thought...
  4. B

    Total energy of a shell charge

    Suppose a spherical shell is kept at the orgin. Its surface charge density is ##\sigma## and radius is ##R##. I think I remember the formula for its electric potential energy is ##U = \displaystyle {Q^2 \over 2R}##. Now I want to derive it. I used ##\displaystyle U...
  5. M

    Conceptual question with Concentric Shell Potental

    Homework Statement Homework Equations The Attempt at a Solution I'm able to arrive at the correct solution here, but I'm fairly sure that my line of reasoning is not proper. 1. For the outermost shell, I discard the inner two shell/charge, since their effective charge is zero. Is this a...
  6. pixel

    Exploring the Distribution of Charge on a Conducting Shell

    It’s been a long time since I took E&M courses and even thought about these things, but a current thread has led me to question the location of excess charge on a conducting shell. Given that there are two surfaces to which charge can move, why doesn’t some charge also locate on the inner...
  7. M

    Shell balances in cylindrical coordinates

    I have a question regarding writing a shell balance for a cylindrical system with transport in one direction (in any area of transport phenomena). When we set up the conservation equation(say steady state), we multiply the flux and the area at the surfaces of our control volume and plug them...
  8. AdrianMachin

    Confusion over electric field inside a charged shell

    I've got confused over a topic in my physics textbook (Fundamentals of Physics). The textbook says if a charged particle is enclosed by a shell of uniform charge, there is no electrostatic force on the particle from the shell. I don't firmly get this, as the book uses a confusing reasoning for...
  9. thrasher1031

    Need some information about Shell Sort

    Hello everyone, i was wondering if anyone knows which uses or applications has Shell Sort and what are the advantages and disadvantages of this sorting method. So far i can't find a lot of information on the applications only that is used in some form in the Linux Kernel and on a library from C...
  10. C

    Shell theorem: Gravity of a hollow planet

    Homework Statement There is a planet (spherical) with a hollow that is concentric with the planet.if the inner radius is r and outer radius is R and mass of the planet is M what would the gravity be outside of the planet at distance x from the center ? Homework Equations Shell theorem...
  11. C

    I Ward identity for off shell photon?

    Consider an amplitude for some subprocess involving an off shell external state photon with polarisation ##\epsilon_{\mu}## and momentum ##q_{\mu}##, stripped of the polarisation vectors so that e.g ##T = \epsilon_{\mu} \epsilon_{\nu}^* T^{\mu \nu}## (##\epsilon_{\nu}^*## is polarisation vector...
  12. U

    Field along vertical axis to hemispherical shell

    Homework Statement A hemispherical shell has radius ##R## and uniform charge density ##\sigma##. FInd the electric field at a point on the symmetry axis, at position ##z## relative to the center, for any ##z## value from ##-\infty## to ##\infty##. The Attempt at a Solution Let ##\theta## be...
  13. R

    Potential of a conducting sphere in a conducting shell

    Homework Statement A conducting sphere, radius R, charged with Q is inside a conducting shell (2R<r<3R) with charge 2Q. Find the electric potential and the energy. Homework Equations \Phi =-\int_{r_1}^{r_2} \vec{E}\cdot\vec{dl} U=\int_{V}E^2dV The Attempt at a Solution I think i got it...
  14. Greg Bernhardt

    Ghost in the Shell Remake: Action vs. Philosophy

    I saw it last night and rather enjoyed it. I can understand how the anime purists dislike it however. One unsurprising criticism is that the film maker opted for more action than further exploring the interesting philosophical aspects of the plot. It could run very deep and slightly disappointed...
  15. A

    Potential inside a hollow sphere (spherical shell)

    Suppose that we have a hollow sphere (spherical shell) whose surface is held at some constant potential V0. What is the potential inside the sphere? I had an argument with my physics professor over this. He claims that the potential inside depends on how far you are from the center and becomes...
  16. cheapstrike

    Electrostatic Potential Energy stored outside a shell.

    Homework Statement A point charge +Q is placed at the centre of an isolated conducting shell of radius R. Find the electrostatic potential energy stored outside the spherical shell if the shell also contains a charge +Q distributed uniformly over it. Homework Equations [/B] E=kQ/r2...
  17. grandpa2390

    Find ELectric field in these regions of a spherical shell

    Homework Statement a thick spherical shell carries charge density k/r^2 a<r<b find E in the three regions r<a a<r<b b<r Homework Equations E dot da = Q/ε The Attempt at a Solution I can't understand why, when integrating, they choose for ii to integrate between a and r, iii and the between a...
  18. Jovy

    Shell Method: Find Vol. of Solid Rotated Around x-Axis

    Homework Statement Use the shell method to set up and evaluate the integral that gives the volume of the solid generated by revolving the plane region about the x-axis. $$y=\frac 1 x$$ Homework Equations $$Volume=2\pi\int_a^b p(y)h(y)dy$$ The Attempt at a Solution [/B] I see that there...
  19. J

    Gaussian shell and electric field

    Homework Statement Homework EquationsThe Attempt at a Solution Okay, parts a-c are zero as they are within both shells. Lets begin with d because i fear I am just repeating the same error in all of the following parts. Part d qenclosed=ρ(4πr^3/3-4πa^3/3) =...
  20. A

    Flux Through a Gaussian Surface

    Homework Statement A metal sphere of radius a is surrounded by a metal shell of inner radius b and outer radius R, as shown in the diagram below. The flux through a spherical Gaussian surface located between a and b is 1.20Q/εo and the flux through a spherical Gaussian surface just outside R is...
  21. jlmccart03

    Magnitude of electric field near spherical shell

    Homework Statement A 10-nC point charge is located at the center of a thin spherical shell of radius 8.0 cm carrying -20 nC distributed uniformly over its surface. What is the magnitude of the electric field 2.0 cm from the point charge? Homework Equations E = kq1q2/r^2 The Attempt at a...
  22. F

    Radiating sphere inside spherical shell - heat transfer

    Homework Statement A sphere of radius r_s is at the center of a spherical shell of inner radius r_i=10\, r_s and thickness s = 10\, {\rm cm}\ll r_i. The sphere has a temperature T_s=1073\, {\rm K} and and an emissivity e=0.90. The inner surface of the shell has a temperature T_i = 873...
  23. J

    Gaussian Shell and net electric field

    Homework Statement Homework Equations σ=q/(4πr^2)→q=σ(4πr^2) E=q/(4πEod^2) E=(4πr^2σ)/(4πEod^2)The Attempt at a Solution So the first thing that i could include was that the point p was inside Shell 1 and therefor would not be affected by Shell 1. So it should be a fairly simple plug in the...
  24. A

    .profile missing in Unix (bash shell)

    Homework Statement I'm playing around in UNIX and I wanted to modify my .profile file in my home directory, but It's not there. I know you type in ls -a to view the hidden files but it's simply not there. Do I just create one? I want it to just display my name every time i log in. Homework...
  25. H

    Line charge within a charged shell (basket case)

    1. Homework Statement An infinite line of charge with linear density λ1 = 6.8 μC/m is positioned along the axis of a thick insulating shell of inner radius a = 2.5 cm and outer radius b = 4.8 cm. The insulating shell is uniformly charged with a volume density of ρ = -667 μC/m3. 1) What is λ2...
  26. U

    Electric field at centre of a hollow hemisphere shell.

    Homework Statement Homework Equations ' The Attempt at a Solution Please excuse the poor writing. I believe it should be legible enough, but if you have any questions, i'll clarify or rewrite it. Please excuse the poor writing. I believe it should be legible enough, but if you have any...
  27. Ian Baughman

    Heat transfer through a cylindrical shell

    Homework Statement An infinitely long cylindrical shell has an inner radius a and outer radius b. If the inside is maintained at a temperature Ta and the outside at a temperature Tb, determine the rate of heat flow per unit length between inner and outer surfaces assuming the shell has a...
  28. Phylosopher

    Two hemispheres, and a shell inside dielectric material

    Hello,I am trying to solve two different questions, and I am having trouble finding the solution: 1- Spherical shell of radius R, have two hemispheres of different charge density. The northerns hemisphere is +σ and the southern hemisphere is -σ. Use direct integration to find V inside and...
  29. Elvis 123456789

    Gravitational Potential due to spherical shell

    Homework Statement What is the gravitational potential both inside and outside a spherical shell of inner radius b and outer radius a? Homework Equations φ = ∫g⋅da = -4πGMencl g = d∅/dr in the r hat direction The Attempt at a Solution I can get as far as getting the gravitational field for...
  30. G

    Shielding an off-center charge with a conducting shell

    Hi. I'd like to show that a conducting, charged spherical shell can shield the field of an inside opposite point charge even if this charge is not at the center. I was thinking about a Gaussian surface just outside the sphere, such that if there were electric field vectors they would be...
  31. Z

    Energy per unit length of a cylindrical shell of charge

    Homework Statement "An infnitely long hollow cylinder of radius ##a## has surface charge density ##σ_a##. It is surrounded by a coaxial hollow cylinder of radius ##b## with charge density ##σ_b##. The charge densities are such that the total confguration is electrically neutral. Using whatever...
  32. O

    Justification for 0 net E field within a charged shell

    SORRY TITLE SHOULD READ: "JUSTIFICATION FOR 0 NET E FIELD WITHIN A CHARGED SHELL" << Title fixed by Moderator (except for the all-caps of course) >> 1. Homework Statement A conceptual query: Considering an irregular shaped conducing shell with a net charge, using Gauss' Law, any Gaussian...
  33. O

    Nonconducting spherical shell with uniform charge

    Homework Statement Suppose the nonconducting sphere of Example 22-4 has a spherical cavity of radius r1 centered at the sphere's center (see the figure). Assuming the charge Q is distributed uniformly in the "shell" (between r = r1 and r = r0), determine the electric field as a function of r...
  34. twist.1995

    Electric field discontinuity in a spherical shell?

    Homework Statement Lets say, there is a non-uniform charge distribution, given as in a spherical shell that has a cavity with radius a and the radius b to the outer surface. I am wondering if the field is discontinuous just on the surface of this sphere. Homework Equations...
  35. G Cooke

    Potential on the inner surface of a spherical shell

    Is there a potential on the inner surface of a charged spherical shell? I know that there is no electric field on the inner surface, as shown by Gauss's Law, but that isn't enough information to say that the potential (V) there is zero since E = dV/dr, so V could be a nonzero constant. If...
  36. ThinkerCorny

    Understanding gravitational potential due to spherical shell

    I know that gravitational potential due to uniform sherical shell at a point outside the shell is equivalent to the potential due to particle of same mass situated at the centre and got proof here http://m.sparknotes.com/physics/gravitation/potential/section3.rhtml. But I was looking for more...
  37. W

    Calculating Heat Transfer in a Tube and Shell Exercise

    Homework Statement Would really appreciate if you could lend me a hand with this tube and shell exercise.[/B] m=0.24kg/s ##D=2.5*10-2m## ρ=850 kg/m^3 cp=2000 J/kg*K μ=2*10-4 kg/m*s λ=0.3W/m*k Homework Equations Dittus-Boelter:Nu=0.023*Re0.8*Prn where n=0.4 heating and n=0.3 for cooling, so in...
  38. G

    Uniform E field for spherical shell.

    Homework Statement In the figure a nonconducting spherical shell of inner radius a = 2.07 cm and outer radius b = 2.51 cm has (within its thickness) a positive volume charge density ρ = A/r, where A is a constant and r is the distance from the center of the shell. In addition, a small ball of...
  39. A

    Minimum distance between bomb and shell

    1. Prolem Statement:- An aircraft is flying horizontally with constant velocity = ##200 m/s##, at a height = ##1 km## above the ground. At the moment shown, a bomb is released from aircraft and the canon- gun below fires a shell with initial speed = ##200 m/s##, at some angle #\theta#. 1)For...
  40. K

    Spherical Shell using Gauss' Law

    Homework Statement An insulator is in the shape of a spherical shell. The insulator is defined by an inner radius a = 4 cm and an outer radius b = 6 cm and carries a total charge of Q = + 9 C (1 C = 10-6 C). You may assume that the charge is distributed uniformly throughout the volume of the...
  41. M

    Rotational Volume Using Shell Method

    Homework Statement Use the shell method to set up and evaluate the integral that gives the volume of the solid generated by revolving the plane region about the y-axis. y = 4 - x2 y = 0 Homework EquationsThe Attempt at a Solution Okay I understand that the region is symmetric about the y-axis...
  42. JulienB

    Electrical potential of a conducting spherical shell

    Homework Statement Hi everybody! I would like to clear up some doubts I have about my electromagnetism homework: A positive point charge ##q## is placed in the center of an ideal conducting electrically neutral spherical shell, as shown in the attached picture. a) Calculate the electrical...
  43. B

    Electron shell further away from nucleus higher Energy lvl?

    Using electrical potential energy =1/4πεo Q1Q2/r , a particle further away from nucleus has lower magnitude of energy Using coulomb's law, a particle further away from nucleus experiences weaker attraction, hence less energy is needed to maintain orbit* around that e-shell compared to a...
  44. B

    Why does an electron shell further away from nucleus has higher energy?

    Using electrical potential energy =1/4πεo Q1Q2/r , a particle further away from nucleus has lower magnitude of energy Using coulomb's law, a particle further away from nucleus experiences weaker attraction, hence less energy is needed to maintain orbit* around that e-shell compared to a...
  45. P

    Predicting spin and parity of excited states from shell mode

    Homework Statement Consider the following example from a previous exam. We are to predict the spin and parity for F(A=17,Z=9), Florine, in the ground state and the first two excited states using the shell model. Ground state: Neutrons: (1s 1/2)^2 (1p 3/2)^4 (1p 1/2)^2 Protons: (1s 1/2)^2...
  46. A

    Gravitation energy of a spherical shell

    I am asked to find the total gravitational energy of a hollow sphere using the fact that the field energy density is given by ##u_g = \frac{-1}{8\pi G}g^2##. Now, ##g = \frac{Gm}{r^2}## in this case and substituting gives ##u_g = \frac{-GM^2}{8 \pi r^4}##. Integrating this over volume will give...
  47. I

    Nuclear shell model, spin and parity predictions

    Homework Statement Not exactly a homework problem but I tried to predict the spin and parity of (the ground states of) ##^{89}Sr##,##^{97}Zr## and ##^{137}Ba## using the shell model and my results seem to differ from the tables. Homework Equations Parity ##\pi = (-1)^l## Figure 4 seems to...
  48. V

    Shell and Liquid Forces: Exploring Equilibrium in a Hemispherical Container

    Homework Statement Homework EquationsThe Attempt at a Solution Considering the upper hemispherical liquid part ,the forces acting on it are , force due to the shell and that due to the bottom liquid . Doing a force balance , force due to upper hemispherical shell = ##\pi R^3ρg -...
  49. kenok1216

    About charge inside a spherical metallic shell

    where are the charge =0? please help...no idea how to do
  50. P

    I Two blackbodies at two foci inside an ellipsoidal shell

    Let's consider two spherical blackbodies at two foci inside an ellipsoidal heat-reflecting shell. Consider the situation that they both have different radii and that their temperatures are such that they emit the same power. Thus, the surface power flux density of each is inversely proportional...
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