Specific Definition and 1000 Threads

I don't have much spear time at the moment, but I came across a SMPS diagram in this thread: https://www.physicsforums.com/threads/quick-question-about-inverter-tx-order-wrt-mains.870309/ And I was trying to figure it out, and I don't want to forget about it before I do. So I was wondering if...

I didn't know where to put this, I figured I'd start here since this area sees traffic that other areas might not see. Someone can move it if there's a better section for it. I'm thinking of an instrument design that has a light path as follows: UV-Vis light source, monochromator or filter that...

How would I get started in object detection of specific objects? I know about OpenCV, it can perform face detection, but what about other objects? I've seen talks on the web of training the program, but I'm not exactly sure how I would do that. I would like to give my software, written in C#...

1. Homework Statement Homework Equations First law of thermodynamics, ΔU=q+W The Attempt at a Solution Ok so, I know that when liquid evaporates, the change in volume is much greater than that when solid melts. And for both cases, distance of separation of atoms increases too, so PE...

Hello, I performed an optimization and frequency calculation at the ub3lyp 6-311g level of theory. The compound has the formula C39H41PS2. Using Molden, I am having a hard time identifying the frequency corresponding to the stretching of a phosphorus carbon double bond present in the molecule. I...

what is the formula to determine the specific activity of radionulcide in sediments

Homework Statement I know that for constant volume ∂q=du and so du=Cv.dT However i don't understand how did we get to ∂q=du by neglecting the vdP term of enthalpy What I am trying to say is, is enthalpy this ∆U+P∂V+V∂P or this ∆U+P∂V? I don't understand since the definition of enthalpy is...

Hello all, I am currently trying to convert brine salinity values in ppm to the corresponding brine density. My understanding is that I can do that using ppm * SG = mg/L . However I do not know how to get the Specific Gravity (SG) of my brine. The data I try to convert has a minimum value of...

Hello Everyone, I will try to explain what am I doing here and I hope someone will understand. ACF - autocorrelation function I'm doing a research about non-parametric methods utility. How they fit and are useful in a different environment. I'm generating time series with different sizes of...

[Mentor's note: this was originally posted in a non-homework forum and therefore does not use the homework template.] Hi everyone, I'm a bit stuck on this question and hoping someone could give me the solution. "A lump of lead, moving with a velocity of 22.0 m/s, is brought to rest. If 55.0%...

Homework Statement My answer is question 3 part c the graph. SHC = c http://www.ocr.org.uk/Images/61757-question-paper-unit-g484-the-Newtonian-world.pdf [See page 7]Homework Equations E=mcdelta theta Power=Energy/Time Therfroe Power*Time = Mass*c*delta theta. The Attempt at a Solution See in...

I am designing 3ph distribution transformer. So for calculations regarding to design, I want specific iron loss. I know how to find out iron loss but that requires initially specific iron loss of material, which i don't know how to calculate. I also searched it on google and in some books but...

According to de Broglie's hypothesis, the matter wavelength could be described by lamda=h/p. But which momentum, the classical p=mv, or the relativistic one p=mv(1-v^2/c^2)^(-1/2) should be used in this equation? Additionally, an even more confusing issue to me is regarding the other relation...

Hi guys. This is my first time posting, so I am sorry if it is in the wrong section. My professor wants me to fin the specific gravity's for gold of 10 karat through 24 karat. He hasn't given us the mass or anything, he just says that we should be able to look them up online. I've been looking...

Homework Statement The specific heat capacity of a metal at low temperature (T) is given as ##C_p = 32\left({\dfrac{T}{400}}\right)^3## (kJK-1kg-1). A 100g vessel of this metal is to be cooled from 20 K to 4 K by a special refrigerator operating at room temperature (27°C). The amount of work...

Homework Statement Homework Equations Clippers equations The Attempt at a Solution I knew that we will put a two diodes( with a dc battery {2.3 V} series) parallel to each other in opposite directions .. but what meant by gain is 0.95 ?

Homework Statement how to calculate the specific volume in this question ? the author didnt gave the ans though. Should i take the volume displaced by the water or volume of the stone ? the specific volume is given by the formula v= V / m Homework EquationsThe Attempt at a Solution

It's possible to calculate the latent heats of fusion and the specific heat of a solution of H2O and NaCl? In some cases, it would have two latent heats of fusion? For example, at 10% NaCl, one at -21ºC and another at -5ºC? Thanks!

This stuff is so confusing! I really wish I were better at math... I had to take precalc math twice, so please try and dumb this down for me. 1. Homework Statement Communication satellites orbit the Earth at a height of 35700km above the Earth's surface. What is the acceleration of an object...

Homework Statement The graph below shows the result of an investigation in which an initially solid specimen of nitrogen absorbs heat a constant rate. Nitrogen melts at 63 K and the specific heat capacity of solid nitrogen is 1.6 kJ kg^-1 K^-1. Homework Equations shc od solid nitrogen = 1.6...

Homework Statement I had a lab where we put 50 grams of a metal smaple into a little bowl and then heated it with steam from a big beaker thing. Anyway, my question is about the errors I got in this lab when finding the specific heat of the metal. I had some high percent errors for Aluminum...

Homework Statement A copper container (mass: 100 g) holds 200 g of water. The temperature of the container and water is 20°C. A 150-g piece of copper heated to 80°C is placed in the water. The water is stirred thoroughly. After sufficient time elapses, to what temperature does the water change...

Homework Statement If a metal is highly susceptible to oxidation, what effect might this have on calculating the quantity of heat transferred to a metal? Use specific examples. Homework Equations Q=mcΔT The Attempt at a Solution Would oxidation change the specific heat of the metal? Since...

1. The problem: If the Sun blows up at some instant and four minutes later we on Earth sit down to eat lunch, these two events are separated by a spacelike interval. The explosion of the sun cannot have influenced us at the time we sat down because it takes 8 minutes for light to reach us from...

Hi everybody, Not sure how to go about the question, so, will start by the narrowest scope... Basically, I am looking for a material with a melting point from 50 to 100C, cheap in volumes :), non-flammable, non-toxic and natural/recyclable. I was going for some kind of wax but flammability (?)...

Homework Statement If you have a body that weighs 100 N dipped in oil that has density equal to 0.8 g / cm³. This same body when immersed in water begins to weigh 60 N. How do I find the density / specific body mass? Homework Equations Solution= 1,3 g/cm³ The Attempt at a Solution Already...

If there are any experimentalists out there maybe you could help? I need to bubble gas through a liquid at ~80 mL/min is there a specific instrument designed to do this? I'm assuming it's some sort of pump, what would it be called in a chemistry lab? Thank you for any suggestions / help.

Part D. I looked up the answer and input it already, which is why it says correct, but i am beyond stumped. No idea how to do this. I know the pressure at the dotted lines are equal and that pressure=force/area. I also know the pressure at an area is equal to whatever is above it so the pressure...

I'd like to begin this by simply stating that I am a complete layman when it comes to ANY of this (I'm just a regular 15 year old high school kid). Recently there has been some fearmongering in a certain game that I play about how this type of clicking causes carpal tunnel syndrome. I am...

I am trying to make specific gravity controls using ethylene glycol and DI water. Ethylene glycol has a specific gravity of 1.113. I want to know the weight in grams of EG to add and then QS with water to achieve 50 ml of a solution with a specific gravity of 1.002. I need a formula please...

Equations: E=m*c* dTheta or T Experiment: I had two beakers of water with one thermometer in each beaker. One beaker had boiling water and the other beaker had room temperature water. I also had a 100g mass. I recorded T1 which was the intial temperature of the cold water. I then put the mass...

Homework Statement Does the specific heat of an ideal gas depend on the temperature only or does it depend on molecular weight and structure ? or both ? Homework Equations PV=mRT , Cp -Cv=R The Attempt at a Solution One of my teachers said it depends only on temperature and the other said...

Hi, To begin with, I am not a native English speaker and have very limited knowledge regarding magnetic fields and thus want to apologize in advance for probable use of incorrect terms. http:// In the picture above, M represents a magnet. S is a material that is not allowed to be affected by...

Homework Statement Define a structure VEHICLE which contains producer, model and chassis number. Store the content of a structure in binary search tree such that the key for storing contains all fields of a structure (producer has the highest priority, and chassis number has the lowest). Print...

Hello, I am currently a sophomore double majoring in Physics and Math at Purdue University. I have a 4.0 overall GPA and would love to earn a Ph.D. and probably a postdoc position in the future. But what should I concentrate in? To which graduate program should I set my eyes on? Here are...

So I have a question regarding the specific heat capacities in thermodynamics. In general the specific heat capacities for a gas (or gas mixture in thermo-chemical equilibrium) can be expressed as, ## c_p = \left(\frac{\partial h}{\partial T}\right)_p \qquad \text{and} \qquad c_v=...

I asked this once before, but forgot the answer. I know the difference between the two. I would like to know why S.G. is even relevant since it seems to give the same answer as density. Ex. Density of a fluid is 10 g/cm3 and density of water at 4C is 1g/cm3 so the S.G. of the fluid is 10 (no...

I've read in my texts that the there are two kinds of Molar Specific Heat Capacities for gases: 1. Molar Specific Heat Capacity at constant Volume ----- ##C_v## 2. Molar Specific Heat Capacity at constant Pressure ---- ##C_p## And in case of Constant temperature there is no point in...

Homework Statement For my physics IA, I am finding the specific heat capacity of water-solute mixtures and finding how the specific heat differs from that of just water alone. I have the mass of the mixture, for example baking soda and water was 914.75g and changed 175.8 degrees Fahrenheit in...

Hello world, I'm currently in my last year of high school and only just getting interested into quantum physics, still learning new things every day. I was wondering if there's a way to measure the specific amplitude of a light wave(Or electromagnetic wave) and what this says about the wave...

Homework Statement Analyze the specific heat of a one dimensional lattice of identical atoms: Show within Debye approximation that the specific heat at low temperatures ( ≪ Θ) is proportional to T/ΘD . Here ΘD=ℏD/ kB = ℏvs/KBa is the Debye temperature valid for 1D, kB the Boltzmann...

<< Mentor Note -- Please read to the end of this thread -- important information about AC Mains connected projects is discussed >> Hello everyone, I am an electrical engineering student (though in the very beginner stage of it), and I could really use some help with understanding inputs and...

Hello! I understand what specific heats are and how to derive them. I just feel that I'm missing a little something in the methodology. Consider the 1st law of thermodynamics and the definition of enthalpy: 1) dU = δQ -δW = δQ - PdV 2) H = Q - VP For the derivation of CV, dV = 0 and the...

I had an experiment to find the specific heat capacity of water. Materials are electric kettle, logger pro, 1 kg water, and set up the time to 240 seconds. The experiment value i got is 4.33 kJ/(kg.K) which is closed to the waters specific heat capacity 4,18 kJ/(kg.K). I wonder what could be...

This is a very fundamental question. I apologize for its simplicity. I did searches on the web but could not find a clear explanation. Whenever I read about the principles of quantum physics, I always come across a statement along the lines of: "electromagnetic energy could be emitted only in...

Homework Statement It is not really a homework question, but rather a translation problem. I searched everywhere, but I still cannot find a good translation into English of a term that is defined as: "In mechanics, the motion of a moving reference frame relative to another (primary) reference...

Homework Statement I figured out 4a, but I'm just struggling a bit with 4b. Homework Equations Relevant websites highlighted above (respectively): http://www.nist.gov/pml/data/handbook/index2.cfm http://physics.nist.gov/PhysRefData/ASD/lines_form.html The Attempt at a Solution This is...

Homework Statement Problem: A sample of dry air has an initial pressure p1 = 1000 hPa and temperature T1 = 300K. It undergoes a process that takes it to a new pressure p2 = 500 hPa with unchanged temperature T2 = T1. Compute the mechanical work per unit mass perfromed by the sample under the...

Homework Statement i have question with part B my working is 13.2 cos tetha (0.86x10^-3)+ 13.2 sin tetha (1.22x10^-3) = 1.95 i gt stucked here. how to proceed? i only have one equation , how to solve two unknown ? Homework EquationsThe Attempt at a Solution

1. Homework Statement A gas (treated as air) powered turbine provides power to a compressor which then sends the compressed air through an intercooler (heat exchanger). Turbine: Gas enters @ 0.03kg/s, 370 degrees Celsius Gas leaves @ 300 degrees Celsius and a "lower pressure" Compressor...