A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable (they can be hammered into thin sheets) or ductile (can be drawn into wires). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.
In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals can become nonmetals. Sodium, for example, becomes a nonmetal at pressure of just under two million times atmospheric pressure.
In chemistry, two elements that would otherwise qualify (in physics) as brittle metals—arsenic and antimony—are commonly instead recognised as metalloids due to their chemistry (predominantly non-metallic for arsenic, and balanced between metallicity and nonmetallicity for antimony). Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). The number is inexact as the boundaries between metals, nonmetals, and metalloids fluctuate slightly due to a lack of universally accepted definitions of the categories involved.
In astrophysics the term "metal" is cast more widely to refer to all chemical elements in a star that are heavier than helium, and not just traditional metals. In this sense the first four "metals" collecting in stellar cores through nucleosynthesis are carbon, nitrogen, oxygen, and neon, all of which are strictly non-metals in chemistry. A star fuses lighter atoms, mostly hydrogen and helium, into heavier atoms over its lifetime. Used in that sense, the metallicity of an astronomical object is the proportion of its matter made up of the heavier chemical elements.Metals, as chemical elements, comprise 25% of the Earth's crust and are present in many aspects of modern life. The strength and resilience of some metals has led to their frequent use in, for example, high-rise building and bridge construction, as well as most vehicles, many home appliances, tools, pipes, and railroad tracks. Precious metals were historically used as coinage, but in the modern era, coinage metals have extended to at least 23 of the chemical elements.The history of refined metals is thought to begin with the use of copper about 11,000 years ago. Gold, silver, iron (as meteoric iron), lead, and brass were likewise in use before the first known appearance of bronze in the 5th millennium BCE. Subsequent developments include the production of early forms of steel; the discovery of sodium—the first light metal—in 1809; the rise of modern alloy steels; and, since the end of World War II, the development of more sophisticated alloys.
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I am trying to read a temperature on a heated cylindrical metal (steel) bar (about 15 mm in diameter) using a pyrometer. However I cannot measure the temperature on this bar. The bar has a rather dim shine on it and I think it affects the reading. Also, maybe because it has a small...
Homework Statement
Determine the specific heat of the unknown metal in the trial.
This is for a lab, when we put a 167.10 g piece of an unknown metal into a Styrofoam cup that had 107.93g of water in it. Recorded the temperature of the water every 30 seconds until it was the same for two...
Homework Statement
A conducting metal ball of radius 2m with a charge of 3μC is surrounded by a concentric spherical shell of inner radius 4m and outer radius of 5m with a total charge of 4μC. Determine the electric potential in volts between the ball and shell at a radius of 3m...
I want to use the ray tracing software ZEMAX to calculate reflection and absorption using thin metal oxide coatings on for example plastic materials. For this I need is the real and imaginary part of the refractive index in the wavelength region 1-10 micrometer for the metal oxides ZnO, ITO...
First of all, Hi we haven't even learned the E = ((hc)/λ) in the physics class but we have this question on our test-exam and I hope that it's fairly easy:
Homework Statement
A metal plate is shone upon with a monochromatic light. When the wave-length is 550 nm a photo-electric effect is...
Does metal powder in water disperse when water is being electrically charged? I think that it might not disperse since water is also charged, the repulsion of water molecule will force it back making net repulsion equal to zero. Am I correct? Thanks for answering.
Here is the diagram that I...
Homework Statement
A spherical metal shell has charge per unit area sigma and radius R. What is the magnitude of the electric field at a distance x from the surface of the sphere? You may include only these variables in your formula: sigma, R, epsilon_0, x
Homework Equations...
24.100kg of copper at 33.000 degrees Celsius receives 310.000 kJ of heat. Calculate the final temperature of the metal.
Homework Equations
Q=mc(t2-t1)
The Attempt at a Solution
I solved the equation for T1
T1=c*m*Q-T2 / C*m
The answer however seems really small and...
Homework Statement
A square metal frame in the vertical plane is hinged at O at its centre as shown in the figure. A bug moves along the rod PN which is at a distance ##l## from the hinge, such that the whole frame is always stationary, even though the frame is free to rotate in the vertical...
Hi folks,
This is probably a fairly basic question with a fairly easy answer. I was wondering if you could use the concept of inductive power transfer using a copper coil on each side of a metal barrier? If that metal barrier was a non-magnetic alloy.
I have attached 2 drawings showing 3...
Dear All,
I have a question about the optical properties of light in a metal.
I need to solve a problem.
Homework Statement
a] Why is the phase shift in a metal neither 0 or pi?
b] And calculate the phase shift of gold with a wavelength of 514 nm?
n_real=0,5 and n_imaginary=1,85...
Homework Statement
Find the potential outside a charged metal sphere (charge Q, radius R) placed in an otherwise uniform electric field E0. Explain clearly where you are setting the zero of potential.
Homework Equations
The Attempt at a Solution
My only problem here is that I...
Homework Statement
Let me first add a picture of the experiment and than try to describe my problem:
So I have two rods (one with a square profile and the other one with a circle profile) and what I do is I apply some force in the middle. The rod bends under the applied pressure...
Homework Statement
A small piece of cesium metal (W=1.9eV) is kept at a distance of 20cm from a large metal plate having a charge density of 1.0*10^-9 C m^-2 on the surface facing the cesium piece. A monochromatic light of wavelength 400nm is incident on the cesium piece. Find the minimum and...
tonequester here. Greetings to ALL.
I have posted about acoustic resonance on my last couple of posts, and have been given much good info. I have one more post concerning concerning this topic.. I am going to do an experiment to find out the answer to my query, IF there is no definitive...
Homework Statement
Of the following solutions, the solubility of calcium hydroxide (s) is least in:
1) 0.4 M calcium chloride
2) 0.2 M barium hydroxide
3) 0.25 M calcium nitrate
4) 0.3 M potassium hydroxide
5) 0.45 M sodium nitrate
Homework Equations
Either I haven't gotten to...
Hi there ,
I have two cast iron crankshafts for an engine I'm building , now even though they are similar in every way , made ofr the same engine etc etc, there is one thing I noticed different and it got my attention ,
I took a stainless steel screwdriver and hit each one of the cranks at...
Homework Statement
I have this question on a practice exam in preparation fora final exam, and I am questioning my solution here:
A hollow spherical metal shell has an outer radius equal to 1.5 m and a
shell thickness of 0.5 m. A +100 nC point charge is located in the hollow
0.5 m from...
Homework Statement
When sodium is dropped into water, aqueous sodium hydroxide and hydrogen gas are produced. Which of the following are correct regarding this reaction?
1) Sodium metal is the reducing agent.
2) There are no spectator ions.
3) In the balanced net ionic equation, all...
I need some information on power dissipation of metal chassis resistors. I have 47 ohm, 50W resistors. (digikey part #A102169-ND)
I hooked them up to 24V. So current flowing is about 0.51A
But the resistors get too damn hot to touch(48-55 deg C, just after a few mins(~5mins). The power...
Homework Statement
A 85 gram piece of metal is heated to 98°C and placed into 200mL of water insulated at 20°C. If the equilibrium temperature is 26.50, find the heat gained by the water.
Homework Equations
200 mL = 200 g.
85 g x 98 degrees celsius x specific heat of metal = 200 g x...
A 0.18m long metal rod is places on some metal rollers in a megnetic field directed into the page. When the rod is moved left with a speed of 1.6ms-1, a current of 0.034 A is measured through the 25Ω resistor.
How would I calculate the voltage when I'm not given the magnetic field strength? V=BvL
metals are generally considered more useful for high strength parts because ceramics break when exposed to sudden shock, but what about when a continuous force is applied to a ceramic and a metal of the same dimensions
by a high strength ceramic i mean a higher hardness than the metal (such as...
Homework Statement
Lightweight bicycle had been fabricated from aluminium alloy tubing, with joints made by adhesive bonding. When the frame fractured near one of the joints, the owner requested that a repair be made using conventional gas tungsten arc welding. Shortly thereafter, the frame...
Read this quote on a major recycler's website:
"During this processing, we separate ferrous materials from nonferrous and further separate the copper, aluminum, brass, stainless steel, and other metals from the stream of nonferrous metals. "
Is Stainless considered non-ferrous? Why? Isn't it...
A one-way mirror is a thin aluminium coating on glass, and the thickness of the aluminium layer is one of the factors determining the reflection coefficient.
Does the reflection occur at the two interfaces (air-aluminium, and aluminium-glass)?
Does aluminium have an index of refraction...
I am confused as to why the following happens:
K_2O + H_2O\rightarrow 2KOH^-
Does the potassium hydroxide no longer react with the water? Why exactly is this a base? How does the potassium end up bonding with hydroxide?
Hello all, thanks for reading. I'm in the process of designing a machine that will move a hall effect sensor in 3 dimensions through a magnetic field and record readings. Before I started the design however, I wanted to see if there would be huge problems in how I envision this machine...
Homework Statement
A metal block of mass m slides on a horizontal surface that has been lubricated
with a heavy oil so that the block suffers a viscous resistance that varies as the 3/2
power of the speed: F(v) = -cv3/2
If the initial speed of the block is vo at x = 0, show that the block...
I am trying to write a program in Action Script that describes the reaction of a horseshoe hitting a stake based on the design of the impact location, i.e., rounded, flat, etc., and the velocity of impact. The location of the center of mass is known. The impact location can vary depending on...
Hello,
I have two images taken of a metal sample that were snapped by a charpy impact test. The image with the black dots (microvoids) was the sample at room temperature, and the flat one was the sample that had been dipped in liquid nitrogen just before impact.
My question is, what role...
Homework Statement
A charge is located a distance 'a' above a sheet of metal. The charge density induced on the sheet of metal is (-2aQ)/(4pi(ρ^2+a^2)^(3/2)).
Since there are no dimensions indicated for this plate, would it be plausible to assume that we are integrating from zero to...
Main reason why semiconductor is used and not a "pure" metal for detec
Hi,
I have question regarding why semiconductor is preferred in the field of radiation detection.
I have read that they can be doped and their conductivity can be manipulated, but I can't see why this is not possible...
Homework Statement
A casing of mass m can glide along a thin metal ring lying horizontally. It has an initial speed of v0. How long a distance s will it glide before stopping if its friction coefficient is μ?
The answer is given as
s = r/2μ * ln( v02 + √(v02 + g2r2)/ g * r )
The task is to...
Today we know that mercury is a metal even though it's a liquid, because we already know its position in periodic table, its ability to conduct electricity, but these features of mercury were not known in ancient times ( for example, in the age of great greek philosophers). Yet it was considered...
Homework Statement
Two initially uncharged identical metal spheres, 1 and 2, are connected by an insulating spring (unstretched length L0 = 1.55 m, spring constant k = 30.0 N/m), as shown in the figure.
Charges +q and –q are then placed on the spheres, and the spring contracts to length L =...
Greetings!
I'm interested in depositing a Line of fine copper powder on a plastic substrate. Due to Limitations of my situation, I want to explore the possibility of using tuned microwaves to fuse the copper particles to form a continuous conductive path. I'm aware microwaves bounce off...
Suppose I have a closed end aluminum pipe of 3cm diameter with .5cm walls
Cylinder is 10cm tall , 8mm of which is submerged in a cold bath of approximately constant temperature of -10°c
I feel it with water at 3°c to 7cm height and stick a cork in it. How long till the water freezes...
So I had to have an MRI today and when your in the machine you wear these headphones so that they can talk to you and stuff, but how could they work with no metal? I realize that there are non-metal conductors but I thought that they had to be doped with metals (to make them semiconductors) so...
When a hand spray painting gun is used to paint say metal tanks, about 80% of the paint is lost in the air.
This not only leads to a wastage of paint, but also the paint partivles settle on other stuff causing paint spots.
What method can be used to reduce this?
One is ionizing the tank...
I've had my phone messed up before by metal and I wondered what the metal did to my phone, I'm guessing it maybe grounded the battery but I'm not sure. Can someone explain what happens when a metal or magnet interacts with electronics? And also is there any way to fix this if that did happen to...
HI I am doing this equation : 14. When a certain metal is illuminated at 3.50x10^2nm the maximum kinetic energy of the ejected electrons is 1.20 eV. Calculate the work function of the metal.
I did this:
E=Ek+W
W=E+Ek
W=hc/Lambda -Ek
=(6.63E-34J.s)(3.00E8m/s)/3.50E2m)-1.20eV
=-1.2
That...
According to the theories that discuss gravity, if humans were to create a solid metal sphere with the same mass as Earth would it have the same gravity as earth?
Would it have to be orbiting something and/or moving to have that same gravity? Or could it be stationary and have the same...
Homework Statement
Consider a thick metal shell with inner radius a = 2cm and b = 4cm. The shell carries no net charge. A point charge of q = 3nC is placed at the centre of the shell. Find the total charged induced on the inner boundary of the shell. Find the total charge induced on the outer...
It's so expensive!
I've received a few quotes.
1st quote was 12 inches wide by 12 inches long by .01 thick. 50$ I need 3 feet of that size. But wow that's expensive for a material that's 75-80% nickel.
2nd quote was 4 inches wide by 12 inches long by .01 thick. 27$ I would need 9 feet at...
I am trying to charge a system of two metal rods, of definite length, placed a certain distance apart. But before setting up the rods and hooking them to any battery, i wish to know the magnitude of charge that will be accumulated on the rods and what is the maximum possible charge on the rods...
Homework Statement
When a charge Q is given to an isolated metal plate X of surface area A its surface charge density becomes σ .When an earthed metal plate Y is brought closed to X ,find magnitude of surface charged density on inner and outer surfaces of X and Y.
Homework Equations...