Questions tagged [metals]

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Understanding electric conduction in tight binding model

Let's consider a system of free electrons moving in a one dimensional lattice with dispersion $\varepsilon(k) = -2t\cos{ka}$, ($a$ is the lattice spacing and $t$ the hopping amplitude). Let's now ...
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Fresnel Equations, Refraction, and Metals

I'm trying to make sense of how the fresnel equations apply to metals. Here are a few of the things I believe I understand: All reflections of light occur specularly. When an object appears to ...
Chris Gnam's user avatar
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Fresnel Equations and an Opaque Surface?

I'm trying to make sense of what actually happens to light when it interacts with an opaque surface. The fresnel equations give us the proportion of light which is reflected off the surface of a ...
Chris Gnam's user avatar
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Vibrating object on optical table

Wikipedia says this about optical tables: Many optical systems require that vibration of optical elements be kept small. As a result, optical tables are typically very heavy and incorporate vibration ...
Riemann's user avatar
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Is metallic hydrogen solid or liquid?

If I squeeze hydrogen superhard with 400-500GPa of pressure, it becomes metal so is that solid or liquid? I know gallium melts on my hand and it's metal.
user6760's user avatar
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Why/how is this crumpled wad of aluminum foil exhibiting strong magnetic repulsion against everything?

Forgive the extreme, potentially unnecessary, detail, but I'm trying to include all possible info to account for all possibilities, as this has driven me mad here. I lined a baking pan with Great ...
Foxhole's user avatar
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Richards rule melting enthalpy

I know that Richard's rule states that entropy of fusion is constant for metals, and that it is ~2.2 cal K-1 mol -1. I am struggling to find the origin of this statement, is it empirical? What is its ...
Aztec's user avatar
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Why and How Moly (Molybdenum) can melt at 800°C inside muffle furnace?

I kept a ceramic cylinder wrapped in a Moly sheet. This whole thing was kept on an another Moly sheet inside muffle furnace. I ramped up the muffle furnace to 800°C in half an hour, kept there for ...
Bhargav Rajyaguru's user avatar
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Extremely strong peak around 10 eV energy of Aluminum crystal in an x-ray inelastic scattering experiment

I conducted an experiment where I measured Bragg reflection for two different atomic planes (200 and 400) of Aluminum crystal at an energy of 10 KeV. Then, in each of these two measurements I shifted ...
cheers's user avatar
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Does electric charge have any effect on diamagnetism?

Diamagnetic materials repel magnetic fields because freely moving electrons or cooper pairs within the material can form eddy currents in response to a changing magnetic field. It is natural to wonder ...
Sidharth Ghoshal's user avatar
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1 answer
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Do mirrors (with metal surfaces) show TIR (Total Internal Reflection)?

[Not a duplicate! Also, the answer to a similar question was unsatisfactory] I was digging into why we don't use mirrors in place of fibre optics cables. Majorly, the answers were as follows: It's ...
Maddy's user avatar
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Can someone tell me why there are two values for the dielectric constant from this website?

I have been looking up at available database that had dielectric constants for metals since I need them for my research and wanted to get an idea of what the values were before I focus on actually ...
Ronald's user avatar
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1 answer
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Calculate Force Needed to Squeeze a set of prongs together? [closed]

I have an anodizing rack that has hundreds of prongs. These prongs are made of titanium and need to be squeezed together in order to place the parts on the rack. I am wondering how I would calculate ...
Jack Duffy's user avatar
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2 answers
37 views

How strength of RF coupling depend on the antenna material?

If we place different materials in the microwave owen, they will get hot at different speeds. For instance meals get hot really fast. What material property decides on the strength of the coupling? ...
Mariusz's user avatar
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Structural notation for multi-element FCC crystal structures

I was wondering if different compound FCC structures share any kind of indicator or structural notation which I could use to find and categorise them. To clarify my problem: the FCC L12 structure, ...
Philipwur's user avatar
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Question about the elasticity matrix in metals

The most general anisotropic linear elastic material has 21 elastic constants. I am working with an HCP material and I found that it has 5 independent elastic constants. I am programming a subroutine ...
Mauro Arcidiacono's user avatar
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1 answer
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Is heat treatment the only means known to man for increasing grain size in steel?

It is well known that steel grains tend to grow larger under heat treatment. Is it possible to enlarge grain size through any other means? I cannot seem to find anything via web search. If steel is ...
artist_and_not_EE_by_training's user avatar
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1 answer
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Metallic behaviour explained by Nearly free electron model

I am having trouble understanding what causes metallic behaviour in context of Nearly free electron model. Is it because 1) In 2d material with fermi level equation is $k_F=\frac{√2πz}{a}$. If for a ...
PhysicsQuestion's user avatar
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1 answer
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Why does gold only glow red after flame is removed?

I was at a jewelry workshop today and saw somebody place a gold ring under an intense flame. Weirdly, the ring looked normal when underneath the flame, but glowed "red-hot" as soon as the ...
WillG's user avatar
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How does electrostatic field affect liquid metal?

I am currently studying electromigration in liquid metals. According to studies that have been done for electromigration in liquid metals, the metal ions are affected by the electrostatic force and ...
Humam's user avatar
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2 answers
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Is it possible that only surface electrons of the metal wire conduct electricity at light speed [closed]

Because if drift velocity of electrons is so slow than the actual speed of electricity which is near the speed of light. Then it might be possible that only electrons at the surface of metallic wire ...
Varun Sharma's user avatar
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1 answer
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Why mobile electron bond so weak with positive ions in metal?

The mobile electrons move very easily in the metal lattice, which proves that they are very weakly bound to the positively charged ions at the lattice. But why is that?
newbieatphysics's user avatar
4 votes
4 answers
892 views

Why can't the charge carriers leave the conductor? [duplicate]

I see that electrons are quite small in size, moreover it is moving fast but I have a question why do free electrons not leave a conductor (like a wire) ? but they can only move at the edge of the ...
newbieatphysics's user avatar
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Scattering processes in $\rm Au$ and $\rm AuPd$

I'm learning about the transport of electrons in solids (especially based on the Drude model), and I was wondering how the different scattering processes that take place in metals vary with ...
user9867's user avatar
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Why is a charge induced on a grounded metallic plate when another charge is placed near it? Why doesn't the charge flow into the ground?

When we bring a charge -Q close to a plate some positive charge is induced on the near surface of the plate to this external charge and some negative charge on the other farther surface. I believe ...
Day's user avatar
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2 answers
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Steel tensile strength explanation needed

Can someone explain to me, how Steel tensile strength works? Lets take "S355" for an example. S355 means, its tensile strength is 355 N/mm2. Which means when i place 355N worth of load to an ...
wtknow's user avatar
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Single metal Seebeck effect in a ring in the presence of a magnetic field

According to the usual Seebeck effect, you can make a loop of wire with two different metals, apply a temperature difference between two opposite sites of the ring and measure a current. See picture ...
Mauricio's user avatar
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2 votes
1 answer
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Why does (oxidized) aluminum have a diffuse optical appearance?

Unoxidized aluminum has a shiny appearance like typical metals. However in air aluminum rapidly oxidizes, giving it a more diffuse appearance (or bidirectional reflectance distribution function). ...
Museful's user avatar
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2 answers
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How is it possible for amorphous metal to have good magnetic properties?

Cross-posted on MMSE. It makes sense to me intuitively that the crystalline structure in, say, grain-oriented electrical steel would yield good magnetic properties. I am envisioning magnetic field ...
artist_and_not_EE_by_training's user avatar
3 votes
1 answer
441 views

What are strange metals?

What are strange metals? Are they something that we have really made, or just a theoretical idea? If they have been prepared in laboratory, then what are their properties (or if they are still a ...
user2800708's user avatar
1 vote
0 answers
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The relation between surface charge density to wave reflection

We know from Guass law that if an electric field hit perpendicular from dielectric medium to a metal, then a charge density develops on the surface. $D_{in} - D_{hit} = \sigma$ Where in metal the Din=...
DDonkey's user avatar
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2 answers
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Why do different metals glow with different colours if all solids have the same emission spectrum?

Why do different metals glow with different colors if all solids have the same emission spectrum? According to my teacher, all solids have the same emission spectrum at the same temperature due to ...
Authentic Melody's user avatar
1 vote
0 answers
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Calculating the amount of Iron in an unknown solid sample

So I want to take a sample of meteorite and figure out it's iron content. Whilst the overall iron content of the larger meteorite is known, how could I go about figuring this out for a given small ...
Epideme's user avatar
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How much will a sheet of gold distort under its own weight? [closed]

The central question I'm seeking an answer to is: what is the minimum thickness required for a rectangular sheet of pure gold, 131cm × 79cm and simply supported on all four sides, so that the centre ...
Daniel T's user avatar
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1 answer
1k views

Why does liquid mercury start spinning in a magnetic field?

I would think this has something to do with the intrinsic quantumagnetic moment of the metal, but I'm curious if every metal would behave this way in liquid state , and if there are any practical ...
Gauge's user avatar
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Hall effect of Metal and Semiconductor [duplicate]

I am pretty much confused in the topic of Hall effect, as it is discussed in Metals and Semiconductor. My question is - Hall effect in Metals is due to electron as they are in majority, so hall ...
Anshul Sharma's user avatar
1 vote
1 answer
119 views

Can total internal reflection (TIR) occur in metals?

Is it possible to get Total Internal Reflection (TIR) when a light beam hits a metallic surface of complex index $\tilde{n}=n_r+n_ii$? If not, is there a way where a light beam can hit a metallic ...
Mikel Solaguren's user avatar
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What causes aluminum to darken when touched?

The rear side of my graphics card (the side that has the HDMI port) seems to be made of aluminum. I noticed that whenever I touch it with my clean finger, I leave a dark trail onto it that is around a ...
SharksFish's user avatar
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Does aluminum darken when exposed to heat?

My graphics card (3060Ti) got these markings that at first looked like mildew to me but after realizing this IO shield (the metal thing) is made of aluminum, I did some research and found out that ...
SharksFish's user avatar
2 votes
1 answer
242 views

Why is a metal pot suddenly iridescent?

I have an old metal pot and for a few days every time I take the pot out of the dish washer it has been quite beautifully iridescent: Any idea why this suddenly occurred and how I can explain it (to ...
halloleo's user avatar
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3 votes
1 answer
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Are solid materials ergodic systems?

It is stated that a system is considered ergodic if it can access all available states with the same energy in the phase space over long periods of time and that time average and ensemble average of ...
Aneli's user avatar
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1 vote
1 answer
107 views

Why are magnesium and calcium crystals, metals instead of insulators/semiconductors?

Consider the outer-most s orbitals for Mg or Ca solid. They will form one band. The 2 electrons in the outer-most shell fill this band. Shouldn't the next p orbital band be above the fermi level and ...
Bohan Xu's user avatar
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2 votes
0 answers
31 views

Pushing molten metal through 0.1 mm hole [closed]

is it possible to push molten metal (eg, titanium), through 0.1mm bore and what would be the force required for a steady & consistent stream of metal? Any mathematical formulas/theory is good.
justanu's user avatar
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2 votes
1 answer
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Electric field deep inside metals in two non-static situation

Consider the following two non-static situations. When we connect a dc or ac source across a metal, an electric field exists inside the metal which causes the electrons to flow through the metal ...
Solidification's user avatar
1 vote
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20 views

Is an object's pressure on a surface, affected by the type of surface?

Is an object's pressure on a surface, affected by the type of surface. For example, if a chunk of metal gave a pressure of $2800 \ pa$ on a table, would it still give a pressure of $2800$ on dust/sand,...
Xiao's user avatar
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Why doesn't the saturation photoelectric current depend on frequency?

From my understanding, even if the frequency of a photon is above the threshold frequency, it is not necessary that an electron gets ejected as the photon may have been absorbed by a metal atom ...
Amadeus's user avatar
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3 votes
1 answer
361 views

Brewster's angle for Metal?

As metal has a high refraction index, it is possible to have Brewster's Angle for Metal when the light incident from the air? Is it possible to derive from any formula?
XEON's user avatar
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-1 votes
2 answers
431 views

Specific heat of mercury and water?

My doubt is , if mercury is denser than water , then why specific heat is lesser of mercury than water , means mercury heat faster than water , if mercury heat faster than water then again , why ...
Bidyut Kumar Purohit's user avatar
1 vote
0 answers
218 views

Magnetic static field simulation software to model metals in Earth's magnetic field

I need to model the effect of steel or iron objects of a given shape disturbing Earth's magnetic field like shown in the pic below. The software, providing a solution, should be free and open source. ...
dizcza's user avatar
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10 votes
4 answers
2k views

Can electrons absorb photons?

I see two broadly opposite answers to this question. One is that electrons can absorb photons, and one is that electrons can't absorb photons (see How many photons can an electron absorb and why?). ...
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