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.
A metal sphere of radius R = 10 cm carries a total charge Q = 0.4 μC.
A. What is the magnitude of the electric field just outside the sphere, and in which direction is it pointing?
B. What is the magnitude and direction of the electric field just inside the sphere?
I have already found...
Homework Statement
A 50-g of ice, initially at 0.0C, is dropped into 200 g of water in an 80-g
aluminum container, both initially at 30C. What is the final equilibrium
temperature? (Specific heat for aluminum is 900 J/Kg*C, the specific heat of
water is 4186 J/Kg*C, and...
Just wondering: If a metal sphere is charged, will the extra charge be uniformly distributed over the volume of the sphere.
i think that it will? but not sure about it being uniformly distributed.
Homework Statement
A metal tube with length 931m is hit with a hammer. On the other end two sounds with time delay of 2.5 seconds can be heard. What is the reason for this? What is the speed of sound in the metal?
Homework Equations
t=L/v
The Attempt at a Solution
I think the...
Dear friends,
I'm having trouble understanding an article by M. Cohen and J. Corkill (Structural, bonding, and electronic properties of IIA-IV antifluorite compounds).
In this article Be2Si (an imaginary compound) is shown to be a metal. The argument used is GROUP SYMMETRY :... group symmetry...
Why is it that one must be under 40 to be eligible for a Fields Metal?
Are they implying old farts can't do math? I wonder what Archimedes would say about this...
good day, this place is great, and i just got questions
an AC electric arc furnace melts metal by way three electrodes and electric arcs generated by potential differences inside the furnace
i had the opportunity to watch one in action and understanding the programming i see it controls...
Homework Statement
A metal ring 4.50 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. These magnets produce an initial uniform field of 1.12 T between them but are gradually pulled apart, causing this...
Homework Statement
Electrons with kinetic energy E are incident normally from vacuum on a metal surface. The work function of the metal is F. Calculate the fraction of electrons reflected from the surface. Neglect any temperature effects.
Homework Equations
The Attempt at a...
I'm having trouble finding a suitable material to keep critters from nesting under our solar panels. Galvanized steel mesh oxidizes quickly because being attached to the solar modules, and plastic mesh just isn't strong enough and looks unsightly. I need a steel or metal mesh that will not...
Metal Bands! Which ones are youre favorites? I envy those of you who lived through the 80's listening to stuff like AC DC, Maiden, Led Zep, GnR. Music was HUGE then! I mean, the money's still there, but rockstars were Gods man! I don't think there's anyone in music today who's as big or iconic...
How do they discriminate between good (targets ) and rubbish, it seems that the orientation of the (Target) can fool the detector, from using one of these detector for many years , i find that the depth of the (Target) is instrumental in the discrimination, and only after years of (detecting)...
Homework Statement
A metal ball with radius R = 0,6 m is charged with Q = 0.15 nC. Find the electrical field as function of the distance r from the center of the ball.
The Attempt at a Solution
Gauss law:
Q = e0*E(r)*A = e0*E(r)*4*pi*R^2
which gives
E(r) = Q /...
I'm trying to get a better understanding of this sort of thing. Here is what I know...
A postive point charge "q" is placed at the center of an uncharged metal sphere insulated from the ground. The outside of the sphere is then grounded from the outside. Then the ground wire is removed. A is...
Homework Statement
21. A certain transmission line is constructed from two thin metal “ribbons”, of width w, a very small distance w<<h apart. The current travels down one strip and back the other strip. In each case it spreads out uniformly over the surface of the ribbon.
a) Find the...
Homework Statement
An inflatable metal balloon assumed to be spherical with radius R is charged to a potential of 1000 V. After all the wires and batteries are disconnected, the balloon is inflated to a new radius 2R. Does the potential of the balloon change as it is inflated? If so, by what...
If you take a screwdriver for example, and hit it a few times near the tip with a hammer or something hard; why does the screwdriver become magnetic?
I was shown someone doing this, and shortly afterwards it was able to attract nails or screws around.
A compact disc contains an extremely thin sheet of aluminum. If you put a larger block of metal in a microwave oven along with a CD and turn the oven on,
a) nothing significant happens
b) only the metal will spark and then melt
c) the metal will melt and the CD will spark
d) only the CD...
Homework Statement
A proton orbits a 1.0-cm-diameter metal ball 1.90 mm above the surface. The orbital period is 1.50 \mu s.
What is the charge on the ball?
Homework Equations
F_{cp} = \frac{m v^2}{r}
F_c = \frac{k q_1 q_2}{r^2}
The Attempt at a Solution
Since the proton is...
Anyone heard of the band Meshuggah? Their beats and timing are very interesting. Like windshield wipers on different cars, oscillating at slightly different frequencies. I Just thought they must be into math and physics.
Homework Statement
A metal plate in the shape shown has a mass of 2.00kg and hangs from a pivot point located a distance d=0.300m from its center of mass. Its moment of inertia, I_cm, about an axis perpendicular to the plate and passing through the CM is 0.210kg*m2. Calculate the magnitude...
the capacitance of two metal sphere system
Homework Statement
What is the capacitance of the two metal sphere system.
*The question has been attached shematically. All the variables are given in the attached file, there is no missing variable.
thx for any help.
Hi all,
I've been struggling with the concept of equilibrium and steady state in a metal wire. Can anyone of you please help me get this important concept down?
I'd really appreciate it. --
Homework Statement
Which of the following statements about a metal wire in equilibrium are...
Hi,
I understand what make metal a conductor of electricity, but what allows it to conduct heat? Is it that it does not absorb heat because it's electrons are easily liberated?
When you put a metal (conducting) spoon inside a microwave, it takes a few seconds, and then you get sparks, that might damage the microwave.
I heard (and cowardly hadn't tested) that putting a spoon inside a cup of water would allow a long 5 minute heating, no sparks and no damage.
The riddle...
Just looking through some old papers and found a problem that I don't know how to solve.
Two identical 1.0-kilogram blocks of copper metal, one initially at a temp OC and the other initially at a temp of 100C are enclosed in a perfectly insulating container. The two blocks are initially...
Zapper, you're so full of assumptions that it's impossible to communicate with you. Did I say it's relevant? It's an apology I think you owe me. I know it was NOT malicious, it probably just didn't compute so you ignored it, until you were reminded of high voltage coils. But apologies should...
Which metallic material will have a maintenance free shine when polished? I want to machine auto emblems so I'm looking for a material that does not go dull when expose to the elements.
Thanks!
I'm familiar with lightning rods taking advantage of the mutual repulsion of charges to shoot off a corona discharge off the sharp end and start a thunder, but why doesn't corona discharge happen to all charged metals? What makes air such a good insulator, when it's just gases, relatively few...
Homework Statement
A steel bar 10cm long is welded end-to-end to a copper bar 20cm long. Both bars are insulated perfectly along their sides. Each bar has a radius of 2.0cm. The free end of the steel bar is maintained at 100 degrees C and the free end of the copper bar is maintained at 0...
[SOLVED] negative rod to uncharged metal ball:
Homework Statement
If a negatively charged rod is held near an uncharged metal ball, the metal ball:
1. becomes positively charged.
2. becomes polar.
3. Effect cannot be determined.
4. becomes negatively charged.
5. is unaffected.
The...
Homework Statement
An infinite, thin, uniformly charged rod (charge density lamda) is situated parallel to a metal plate at a distance d above it. Calculate the E-field close to the surface of the plane as a function of perpendicular distance to the rod.
The Attempt at a Solution
I...
hey guys i was wondering if anyone could help me with this question, kinda got stuck
Homework Statement
Figure 24-31 shows a section of a long, thin-walled metal tube of radius R = 5.56 cm, with a charge per unit length λ = 7.34 x 10-8 C/m. What is the magnitude E of the electric field at...
[SOLVED] Thermal Expansion Problem
Homework Statement
A metal ball is just able to pass through a metal ring. When the ball is heated thermal expansion will not allow it to pass through the ring. What would happen if the ring rather than the ball, were heated? Would the ball pass through...
hello!
i am quite new to material engineering and so my question might seem a bit too obvious. her it is:
i have a metal ring-(picture1(304 stainless steel))
i need to know what property of the metal defines the ring's resistance to "opening"- like shown in the second picture
thank you very...
Hello! I am a grad student and am trying to acquire some Aluminum Metal Matrix composites with Boron Carbide reinforcement (15-20%) for research. I need the material to be in 1/4" thick sheets. Does anyone know of any companies that sell this sort of material?
Thanks!
A piece of metal with a mass of 1.50 kilograms, specific heat of 200 J/kg · C°, and initial temperature of 100° C is dropped into an insulated jar that contains liquid with a mass of 3.00 kilograms, specific heat of l,000 J/kg · C°, and initial temperature of 0° C. The piece of metal is removed...
Dear Sir,
This is Thangamani, doing research on sensor design. I have gone through Mr. Robert Dean (RF CMOS Designer, MEMS Optical, Inc) article that available on internet ( if not mistaken its from MEMS forum) discussed analytical solution about rectangular membrane. Since i am...
force exerted on walls of metal box...please help!
1. Homework Statement
A cubic metal box that has 20-cm-long edges contains air at a pressure of 1.0 atm and a temperature of 300 K. The box is sealed so that the enclosed volume remains constant, and it is heated to a temperature of 400 K...
dear all
can anyone tell me..
if i have a transmission line passed above a metalic surface, there will be a parasitic capacitance between the line and the surface. and it induces interference how can i measure it.
and if there is any refrenece about the allowable induce voltage...
Homework Statement
A thin, rectangular sheet of metal has a mass M and sides of length a and b. Use the parallel-axis theorem to calculate the moment of inertia of the sheet for an axis that is perpendicular to the plane of the sheet that passes through one corner of the sheet
Homework...
Homework Statement
Two 10-cm-diameter metal plates are 1.0 cm apart. They are charged to +/-12.5 nC. They are suddenly connected together by a 0.224-mm-diameter copper wire stretched taut from the center of one plate to the center of the other.
A)What is the maximum current in the wire...
Homework Statement
* A 14.0kg block of metal measuring 12cm x 10cm x 10cm is suspended from a scale and immersed in water. The 12.0 cm dimension is vertical and the top of the block is 5.05 cm below the surface of the water.
(a) What are the forces acting on the top and on the bottom of...
A square metal plate 0.180 meters on each side is pivoted about an axis through point O at its center and perpendicular to the plate.
Calculate the net torque about this axis due to the three forces shown in the figure if the magnitudes of the forces are F1 = 18.0 N F2 = 27.0 N and F3 = 14.0...
Homework Statement
A metal container, which has a mass of 8.0 kg contains 14.3 kg of water. A 2.9-kg piece of the same metal, initially at a temperature of 190.0°C, is dropped into the water. The container and the water initially have a temperature of 15.1°C and the final temperature of the...
Hi, I carried out a couple of experiments with unknown group 2 salts; X and Y
I added dilute NaOH to each of the salts which were now mixed with 1cm^3 of water; Y formed a precipitate (initially the solution was colourless as the solute had dissolved) whilst X turned colourless (X's...
Homework Statement
If I have the horizontal range and a launch angle, how can I calculate the initial velocity of a metal ball if the vertical displacement is not zero?
Homework Equations
The Attempt at a Solution
My teacher marked my answers to this assignment as wrong. He wouldn't explain why, so I hope you guys will be kind enough to point me in the right way :smile:
The reading of the sensitive ammeter was found to be 0.002mA. Radon-220 isotopes are introduced through the valve and it releases...