Solid Definition and 1000 Threads

Find the volume of the solid in the first octant bounded by the parabolic cylinder z = 25 − x2 and the plane y = 2. I already solved it and got 710/3 as my answer, I just wanted to make sure its the right answer

ZapperZ submitted a new PF Insights post Do Photons Move Slower in a Solid Medium? Continue reading the Original PF Insights Post.

I understand why an impure solid will have a decreased melting point, however, in my recent organic chemistry lab section I mixed two finely ground pure solids together and observed that the mixture melted at a lower temperature than either pure solid. I understand this in principle, but...

Homework Statement Hi everybody. I am triying to do the next exercice: Given a unit cell of Ice X and knowing the positions of the atoms on it, find the expression of the structure factor for a difraction peak as a function of its Miller's index and the atomic form factors fO and fH. Will...

I was wondering , are there any materials , metal or others, that have ions as the charge carriers that form current instead of electrons as in most metals.? and are the ohmic resistance in room temperature for example similar to materials were current is formed by electrons or is the resistance...

Hi everyone, I am a fourth year undergrad in physics. I am strongly considering graduate study in materials science, and I am wondering which course might have more impact both on my future studies and on admissions. The materials course seems like a broad overview of the subject, going over...

I am trying to undersand Ashcroft's derivation of energy density on page 38. I am following most of the arguments save EQ 2.30. Where did the vector go? I did follow my professors argument for converting to polar/spherical when the argument of a function is a modulus of a vector — exploiting...

What is the best book in solid state physics that contains problems and solutions?

Homework Statement Show that the conduction and displacement currents cancel each other for a spherical radioactive solid emitting charged particles radially outwards Homework Equations Maxwell's equations Current density (j) Displacement current density (jd) The Attempt at a Solution I...

Hi everyone, first time post here. I know (or at least think I know) that strings can sympathetically resonate at harmonic intervals. For example, a string whose fundamental is 400Hz is able to resonate at 800Hz if it's excited by a 800Hz source. Maybe I'm wrong on that as well? heh.. Anyways...

Homework Statement Two spheres look identical and have the same mass. However, one is hollow and the other is solid. Describe an experiment to determine which is which. Homework Equations mgh= ½ m v^2 + ½ I ω^2 where I= 2/3 mr2 for a hollow sphere I=2/5 mr2 for a solid sphere The Attempt...

Hi all, I am trying to work out the stress on a shaft when a compressive force is placed on it such as a taper lock or press fit. I have looked at all the thin and thick wall section formulas and they seem ok. I am not sure what happens when the internal radius becomes 0 and its a solid shaft...

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...

Hello I've been wondering how certain solid state lasers could have a continuous lasing action (Nd YAG laser for instance ) If so,the understanding that the best lasing conditions are when the temperature Is lowest gets disproved(considering that a commendable quantity of heat is produced during...

Hi, this is my modified post since I've been told that I have to use certain format. I hope this is good now. Homework Statement Copper (conductor) sphere of radious R with an spheric bubble inside placed at distance c from the center, with radius b. The metalic sphere has charge Q.Homework...

I have been pondering in my mind that if mathematically a partial is made up of an uncountable infinity of space, then how do particles not dismantle and keep a solid a "solid"? This might be a confusing question so, sorry.

Hi I m studying modelling the viscoelastic passive properties of vascular walls and there is question! Why does Maxwell andKelvin-Voigt fail to represent a solid? and also what steps are required from a numerical point of implementation point of view , are required to turn an elastic model...

Hi all, I'm brushing up on some thermodynamics, and having been reading up on the interpretation of temperature as derived from kinetic theory. I can follow the derivation for an ideal, monatomic gas which relates temperature to the average, translational kinetic energy of the molecules. Most...

I was wondering if anyone could help me with this. I'm stuck and not sure where to start/how to go about it and finding the integral as well... Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis. y=5x^2,x=1,y=0, about the x-axis

The problem is to find out the solid angle ω subtended by a disc of radius a at a point P distant z from its centre along its axis. α is the semi-vertical angle of the disc at the point P in question. The answer is supposed to be ω = 2π (1 - cos α), according to an online text. However, I find...

Is strain always recoverable in a viscoelastic solid? For instance, I thought in the single-branch Maxwell model, there was unrecoverable strain ... or am I wrong? And then if you use a two branch Maxwell model (one spring, one spring + dashpot), all strain must be recoverable, correct?

Dear PF Forum, I have no background in physics :frown: In http://math.ucr.edu/home/baez/end.html 1. If an Earth size object is left alone (assuming the Sun won't swallow it 2 billions year later). In 101500all of it atoms, oxygen (majority abundant in earth, right), silicon, nitrogen (abundant...

do each point in solid have a special energy state?

Homework Statement Find the mass of the solid bounded from above z = √(25 - x2-y2) and below from z = 4, if its density is δ = k(x^2 + y^2 + z^2)^(-1/2). Homework Equations m = ∫∫∫δdV The Attempt at a Solution The plane z = 4 is transformed into ρcosφ = 4, that is, ρ = 4secφ. And x^2 +...

In a solid, is electron's wavefunciton confined to a molecular orbital between atoms or is it delocalized and extends over the volume? According to valence bond theory, electrons are localized in bonds between atoms. But according to band theory (or Bloch wavefunctions), electrons are...

Homework Statement Use cylindrical coordinates to find the centroid of the solid. The solid that is bounded above by the sphere x2 + y2 + z2 = 2 and below by z = x2 + y2 Homework Equations x = rcos(theta) y= rsin(theta)[/B]The Attempt at a Solution I am having trouble trying to find the...

[Moderator's Note: Changed level of thread to "Advanced" based on the topics being asked about, all are graduate level topics.] I feel that I have an inadequate understanding of many important concepts in condensed matter physics, so I want to try to learn at least the most basic parts. So what...

Homework Statement the difference in length between an aluminium rod and a copper rof at 0 degreeC is 2cm. If they have the same difference in length at any temperature difference, what are the length of the 2 rods at 0 degreeC.? Al - expansivity = 20*10^-4 K^-1 Cu- expansivity= 15*10^-6 K^-1...

Hello,I'm new here and this is my first post. I am a freshman electronics and communication engineering student.I didn't study any quantum mechanics or solid state physics before(not in high school). But for my first year course i need to study solid state physics.The books we are suggested to...

Homework Statement http://prntscr.com/7rtrep http://prntscr.com/7rts95 Homework Equations theta = TL/GJ t(max)= Tc/J The Attempt at a Solution The two questions i have are rather similar so i put them up at the same time, i hope that's okay. For the first one ( the first link) i started by...

For a physics problem, I need to calculate the solid angle subtended by an oblique cone (cone where the apex does not lie on the line perpendicular to the cone's base from the center of the base). Consider the following problem: I have a 2D disk which emits light in an ever growing hemisphere...

As I understand it, the BB says the universe came from a tiny ball of stuff. Is it correct that no one has an explanation as to where the ball of stuff came from? Is it also correct that the BB is still speculation and subject to revision, even potentially discarding altogether?

Is there a solid that has a density of or below the density of air or any gas?

Homework Statement 1.The maximum energy (per unit volume) that can be absorbed by the steel alloy without sustaining permanent deformation is _______ lb/in^2 1.4. The maximum energy (per unit volume) that can be absorbed bythe steel prior to fracturing is _______ kip/in^2. . Homework...

Homework Statement Ok, don't get angry with me. The original problem is from Solid State Physics but my problem is very well in "Introductory physics". Here is the problem: The chain consists of molecules, which has three atoms, each with mass ##M##. Spring constant between the atoms inside...

I have to calculate the centre of mass of the drawn hemisphere. I don't understand where I make mistakes. The process I followed on the above image is the following: (I) Here I simply translated position vector components from cartesian to polar coordinates. (II) Formula of x-component of...

In the discussion of calculating specific heat for a solid, it is assumed that the whole solid body is a molecule with N atoms and the Hamiltonian of this solid is similar to that of a molecule with N atoms, i.e. ## \mathcal{H}_1=\mathcal{V}^{*}+\sum_{j=1}^{3n}...

In solid state physics, I learned that the velocity of a bloch electron is ##\frac{\partial E(k)}{\partial k}##, where ##E(k)## is the energy dispersion. This formula is derived on the basis of the assumption that electrons is a wave packet of bloch state in solids. However, I have a question...

Homework Statement I'm having trouble figuring out if a solid is a molecular solid or network covalent solid. Classify the following as a network covalent solid or a molecular solid: 1. CO2 2. SiO2 Homework Equations Molecular solid held together by intermolecular forces Covalent network...

Homework Statement A jeweler heats 25g of pure gold until molten. If the initial temperature of the gold is 22 degrees celcius, calculate the amount of energy required for the process. Homework Equations c = 129 Lf= 64 500 Lv = 1578000 Tmelt = 1064 The Attempt at a Solution Q = mct =...

In nuclear physics we have talked about the liquid drop model and the fermi gas model. My question is can a Fermi liquid and a Fermi gas be directly described using these models? Are they the same thing? i.e. If I wanted to decribe the difference between a fermi gas and a fermi liquid could I...

I have found via integration that the y coordinate is $$y =h/2 = 120 mm$$. The x coordinate is $$x = \frac{-4r}{3\pi} = -51.9mm$$ and the z coordinate is $$z = r - \frac{4r}{3\pi} = 69.1 mm$$. I have no answers in my textbook so can't confirm whether i am correct or not.

Homework Statement The problem is asking to find the change in temperature of forged cylinder. I know how to calculate this, , however I am struggling to find the work done on the cylinder, which is required to solve this problem. The cylinder is annealed copper, which is compressed from a...

Hello, In which way nano and solid state physics improve technology? where we use statistical physics more in nano physics or particle physics? where we use quantum mechanics more in nano physics or particle physics? which major is more enjoyable nano or particle physics? which major is more...

Homework Statement Investigate electronic bands in one-dimensional crystal in weak potential $$V(x)=\sum _n V_0(H(x-na)-H(x-na-a/3))$$ if ##H(x)## is Heaviside Theta function. a) Determine primitive cell, reciprocal mesh and first Brillouin zone. b) Calculate the difference between energy...

Homework Statement [/B] ZnS crystalizes in the B3 type structure with the space group is F¯43m. This structure is shown below and can be regarded as the bi-atomic form of the diamond lattice (F d¯3m). Upon applying a force along the [1,1,1] direction, the crystal might experience a change in...

To my understanding, QED is about electromagnetic interaction, and in a solid system, the interaction is only electromagnetic So why there are stills lots of research in solid state physics ? Is there something not explained by QED ?

we can use avogadro's law and gay lussacs law to find atomicity of gases but what about solid elements

Homework Statement This is a problem regarding transient heat conduction in an undefined semi-infinite solid, initially at a temperature T0 whose surface temperature is suddenly raised to a new constant level at Ts. I also supplied the problem as an attachment for ease in explaining the...

Hi all, I need help finding a formula to find the volume of a solid that has a fixed width and depth but 4 different heights. To see what I mean, please take a look at a sketch I drew below. Thanks.