Lead Definition and 292 Threads

Homework Statement The ‘half-thickness’ tells us the thickness of a given material needed to absorb half the incident photons from a particular source. Find the average distance of a gamma ray in lead before its first collision. I have a value for the half thickness (and equivalent half...

If you want to soldier something, then, how can you check to be that whatever you are soldering has no lead present?

How are the cells (say 2V) of a typical lead acid battery connected in series to increase voltage to 12V when all the neg. plates are connected together and all the positive plates are connected together which as I understand is the principle of connecting two batteries in parallel (pos...

The model is a vampyr 731i electronic I can't find the technical information online Howstuffworks.com only gives the information that the fan motor is electrical What sort of motor is used in the lead retraction device?

Hello all, i need one suggestion for shielding of a gamma source. I have a gamma source with initial activity of 50 mCi=1.85X10^9Bq. What thickness of lead needed to protect myself! I used the formula I(x)=I exp(-kx). I=50mCi; k=37.6 cm^2/g (linear attenuation for 122 keV) and x the thickness...

(I think I might have asked this a few years ago...) Looking for a home test for lead. I've got this lump off metal that I'd like to test. I bought a lead test strip but it's inconclusive - it says there's low concentrations of lead even if I follow all directions and test twice using two...

Cerebral small vessel disease...does it lead to dementia? My mum (51) has recently had a TIA and has been diagnosed with CSVD. She has some dysphasia and memory trouble. She has had bloods...all normal, lipids at 5.5 (put on meds to bring it down to 3.5), carotid dopplers - normal, all vitals...

Hi everyone, I've recently been bugged by a question I can't seem to find a reasonable answer to. It's about an apparent contradiction between how the wave equation is supposed to evolve in time according to the schrodinger equation and the measurement formalism in QM. Suppose I have any...

lead nitrate? how can i make lead nitrate by easy way>>>>>>>>>> ,,,,,,,,THANKS

is it safe to say that the lead photon emitted from a moving emitter will always be at a distance from the emitter equal to c x time (from when the first photon was emitted) no matter what the emitter does? Also, will the photon emitted at the end of the first second always be at a distance...

Homework Statement Consider the charging of a lead-acid batter at atmospheric pressure and room room temperature. 2PbSO4 +2H2O -> Pb + PbO2 + 4H+ + 2SO42- How much electrical work must be provided to produce one mole of lead? The Attempt at a Solution We're given the values of Gibbs...

This is something which has been a question to me that I don't seem to have stumbled across anything about myself: How and when did/do the elements above Iron get created? I've come across mention about the elements up to iron being generated by the process of fusion in stars. I assume...

in a problem using the Rutherford scattering experiment, i Need to find what the turning distance would be using lead instead of gold. I have that gold has a Q= 79e, what would the Q = ?? for lead?

http://edition.cnn.com/2009/POLITICS/05/14/iraq.torture/ It is said that torture leads to the answers that the torturers want to hear. Could it be that these illegal procedures led to the biggest foreign policy disaster in US history - the invasion of Iraq? Was Cheney determined to torture...

Hi, When the core of a star shrinks during its evolution, does it always lead to the expansion of the star? If not, why? What cases would cause it to expand? Thanks in advance, Maria

Hello, For my lab I was instructed to weigh out 1 gram of Lead Tartrate (PbC4H4O6) and place it into a test tube. I was then told to hold the tube over the lit burner until the lead tartrate was completely black and smoke was no longer forming. I was then told to pour the black powder into...

What thickness of lead is needed to neutralize brief exposure to gamma radiation, or at least reduce it to below 5 gray?

How is a series RC network acting as a lead network & a parallel RC combination acting as a lag network ?

Homework Statement A 16.00 lead sphere is hanging from a hook by a thin wire 3.20 long, and is free to swing in a complete circle. Suddenly it is struck horizontally by a 5.50 steel dart that embeds itself in the lead sphere. What must be the minimum initial speed of the dart so that...

I got this idea that I could maybe replace the heavy lead acid battery on my motorcycle with a lithium ion polymer battery. I found that you can buy batteries for RC cars that match the power requirements. The lead acid battery is 12 volts, 6Ah. It seams that L.I.P. batteries for RC cars are...

I usually plate lead dioxide on carbon to form my anodes, however, I was wondering if anyone knew why one can't use a lead strip and let electrolysis oxidize the surface to lead dioxide? It is too simple for it not to be used already. But I did make a set of lead acid batteries by just using the...

Lead in the form of -for example- Tetra ethyl lead has long been used as fuel additive, ultimately causing soil pollution. There is concern that this lead ultimately settled in wood during the growing process, which may have led to unacceptable concentrations of lead in wood. So, it would be...

1. Determine the half value thickness, X(1/2) for lead where; I = 0.4 MeV u = 1.59cm^-1 2. using; I = Io e^-ux3. ln(I/Io) = ln(e) -ux ln(2) / -1.59x10^-2 = X(1/2) => X(1/2) = -1.7523m Is that right?

I recently disassembled my Big Screen CRT projection tv. I have been well aware of the danger of the capacitors in CRT TV's and I managed to take the TV apart and remove the capacitors all without killing myself. However, I was doing some more reading online and it seems there is another danger...

Homework Statement So the question is what volume is required to make a lead spherical balloon float. It is filled with helium, the P=10^5 Pa, the Temp is 300K and the thickness of the lead balloon shell is .1mm Any ideas on sending me in a direction with this one?Homework Equations The...

Hi, can someone tell me what are the optimum settings for a charger to charge a 24v 12ah Lead Acid Battery? I know that the voltage stays the same. I just need to know what current will cause the faster charging and, at the same time, won't destroy the battery.

Hello, To measure the augmented limb lead voltages aVr, aVl and aVf two resistors of value R are used on the (-) side and a resistance R/2 on the (+) side. Could anyone please explain me what is the purpose of the R/2 resistor. I attached a picture. Thank you

I came across this interesting article to convert a standard lead acid battery into alkaline: http://blog.hasslberger.com/2007/01/how_to_convert_a_lead_acid_bat.html Seems very promising. Not only does the capacity increase slightly, but the battery also withstands deep discharges much...

Have about a ton of powder - want to make fishing sinkers :smile: Is there a cost effective process to recover the lead? What would the by-products be and are they as toxic as the white lead powder? Thanks for the help! hawkin

Homework Statement A lead ball is dropped into a lake from a diving baord 5.0m above the water. After entering the water, it sinks to the bottom with a constant velocity equal to the velocity with which it hit the water. The ball reaches the bottom 3.0 s after it released. How deep is the...

Hi everybody,while working in nuclear lab when i was watching a source(Cs(137)) i found that in front of that a transparent sheet is placed while the whole covered with lead,so that radiations not emit at large from any other side.So can you tell me what's the reason behind that lead is taken as...

Homework Statement A sculptor has come to you with a problem, because she knows that you are such a good physics student. She wishes to make a lead casting of an object which will require 2 kg of melted lead. If the lead was stored in her basement at approximately 55˚F, and it is to be...

I was just about to spoon some vinagrette onto my salad today when I see this big warning from the State of California that balsamic vinegar products contain lead. How the heck is lead getting into my salad dressing? This is the first time I've ever seen this. Are other U.S. states putting out...

Hi, I'm not very good at QFT, but starting from Dirac's QED Lagrangian (look for example at: http://en.wikipedia.org/wiki/Quantum_electrodynamics" ) L=\bar{\psi}\left(\gamma^{\mu}\left(i\hbar\frac{\partial}{\partial\mu}-q(A^{ext}_{\mu}+A_{\mu})\right)+ mc\gamma^0...

Hello, I was wondering if someone could help me understand how insoluble lead (II) chloride dissolves in hot water. I know it's probably dependant on temperature, (increase in temperature = increase in solubility) but is it affected by the chemical structure of the compound as well?

First of all, I have to say hello to all of you. I am from a foreign country so my English isn't so good. So my problem will probably seem very funny and easy to you, but it's very hard to me. I've got absolutely no idea about it and I'd be very thankful if you could help me out. So here it is...

I currently have a set up where I have attached a permanant magnet dc motor to a bicycle. The motor is attached through a diode to a 12v regulator and then to a 12v to 240v inverter. Everything works fine and I can power up my devices. But I have been told that if I connect my 12V lead acid...

Homework Statement Homework Equations How do you know when a given set of initial values for an ODE produce a periodic solution? The Attempt at a Solution I tried playing around with it for a bit and then searching the net but came up with nothing

Homework Statement A tin can has a total volume of 1200 cm^3 and a mass of 130g. How many grams of lead shot of density 11.4 g/cm^3 could it carry without sinking in water? Homework Equations Bouyancy force= mass of displaced fluid*g The Attempt at a Solution no idea!

the acid solution in a fully charge lead storage cell contains 33% h2so4 by weight and has a density of 1.25g/ml. cALculate its molarity

This is part 2 of a 2 part question. Suppose a measurement setup was given (It's just simply a setup with of a 2 lead system measuring a person's heart). The lead vector for this setup is given a v = [x, y, z] and there is also a dipole vector, p, but those numbers are not important. If under...

Can over running of array lead to the catastrophic failures? If ‘Yes’ then why does not C++ provide bound checking on array operations and who is responsible to prevent array overruns?

Gold has atomic number of 79 whereas Lead has 82 but lead has 11.000kg/m3 density as to Gold's 19.000kg/m3. How come??

Hillary Clinton's third place showing yesterday in Iowa might not be the show stopper some have anticipated. There are reports that the campaign is in disarray and struggling but her overall political apparatus is the envy of all the candidates in the Democrat party. I think she will do much...

Witten argues one of string theories great achievements is that it shows that topology can change. Which is fine, but is there any observational evidence (i.e from astronomy or HEP) or any experimentally testable predictions on topology changing? Is there any physical evidence for topology...

My square wave is lagging/leading the sine wave (depending how you interpret it). i want to make the transition of my square wave be at 0 deg for the sine wave. right now the square wave transitions at 130 deg of the sine wave how can i shift this so that it transitions only at 0 deg or 360...

Or at least an investigation. Remember https://www.physicsforums.com/showthread.php?t=83110&highlight=plame" Did anyone here pay attention to the http://www.truthout.org/docs_2006/013107Z.shtml" to Simple Scotty? Here is an interesting point by...

Hi all, I'm now very busy trying to findout how to block external RF at my apartment room. I'm on 23rd floor. A huge radio boardcasting tower (714KHz, 90MHz) is just 20 meters away running along with my building. It's higher than 25 floors. I know that many GROUNDED conductive surface can...

Hello, This is my first time posting here. My HS has a Project Lead the Way sequence. I am currently enrolled in Honors Drawing & Design for Production, I am considering taking the rest which are Computer Integrated Manufacturing, Digital Electronics, Principles Of Engineering and Engineering...

Homework Statement 5 kg of lead shot at 97.9 °C are poured into 5 kg of water at 26.0 °C. Find the final temperature of the mixture. Use cwater = 4187 [(J)/(kg·° C)] and clead = 128 [(J)/(kg·° C)]. Homework Equations The Attempt at a Solution How do I start this?