Capacity Definition and 664 Threads

We have the parameters,current =10^-3A,V=15kv,number of electrons=6.25 X 10^15,velocity=7.3 X 10^7,specific heat capacity of the liquid=2 X 10^3,c=3 X 10^8,h=6.63 X 10^-34,mass of electron = 9.11 X 10^-31. Now the question says,in an x-ray tube having those parameters,find the rate at which...

Homework Statement 1.0 g of water at 28 degree celcius is placed into a 200g aluminium can at 300 degree celcius. What is the temperature of the aluminium can after all the water vapourises? Given the specific heat capacity of aluminium, 900 J/kg/degree celcius and water, 4200 and specific...

Homework Statement This is a problem I made myself and it's really confusing me. You have 100mL of water and place it in a calorimeter of low specific heat capacity. You put another 100mL of water in another calorimeter of high specific heat capacity. Assume in both instances that the water is...

Hello PF, Is the following calculation correct for the amount of time it would take to raise the temperature of a given mass of material? Q = heat in J W = watts m = mass in kg c = specific heat in J/kgC Tf = temperature final Ti = temperature initial Q = m * c * (Tf - Ti) m = 5...

Homework Statement QN1. A system consists of N weakly interacting subsystems. Each subsystem possesses only two energy levels E1and E2, each of them non-degenerate. Obtain an exact expression for the heat capacity of the system. QN2. A system possesses three energy levels E1 =E , E2 =...

1. Propane vapour (1kmol) at a pressure of 40 bar and 230 C expands adiabatically to 0.25 bar and 95 C. Determine a)W, b)Delta S, c)The amount of work obtained if the expansion were done reversibly from the same initial conditions to the final pressure of 0.25bar 2. I am not sure how to...

Homework Statement please see attached! :) Homework Equations The Attempt at a Solution Ok so I've done the first part and the first bit of the second, so I've shown that theta = 2 uBB/kb My problem is in the next bit where it asks you to work out Tpeak. I guess you have...

I have a problem understanding how we can say that an object has energy of x joules because energy depends on the frame of reference right ? I mean let say a bird is moving with velocity of 5 m/s if I were a stationary man I would observe that it has a kinetic energy but if I were moving with 5...

Hi, I have read Lift-it catalogue and I found out it is very professional and useful . I have some questions in the subject and I'll be grateful for professional answers. I found out that there is a direct relationship between SWL and the width of the strip (1600 lbs/in of width for nylon...

What is the carrying capacity of Earth? How many human can be supported with the current level of technology? What level of standard of living should we aim for? Is over shoot possible? I have no computer model to study so I can not answer the first two questions. I would like to have at least a...

This is not a serious question, but I think evolution has given them too much advantge by allowing them to fly as well. I mean they are bad enough without fying. Also do they get tired when flying, they don't do it very often.

Homework Statement The question asks whether it is always true that dU=C_VdT and their answer is no, because from the 1st law of TD we derive that: dU=C_VdT+\left(\frac{dU}{dV}\right)_TdV However, if we hold the volume constant, dV=0 and therefore the second term disappears, is this...

"A rule of thumb is that for every ten-percent increase in efficiency for rocket fuel, the payload of the rocket can double.” Can someone assist me with a simple formula to model this rule-of-thumb? What happens to the payload if the rocket fuel efficiency increases twenty to thirty percent?

I am going to modified the pristine montmorillonite (MMT) by using cationic surfactant. However I am confusing on the way to calculate the weight of the surfactant. I have been searching hundred of journals but couldn't get any information on how to calculate it. For example: MaterialsThe...

I have the equation for heat capacity for constant volume and pressure. Cv = Cp -R So for Cp I have the units J/k and for R the units are J/k mol. So my question is related to that mol. Is it right that I need to get rid of that mol? if so how? Does it involve Avogadro's Constant? Or do...

From what I understand, if a photon hits let's say an atom of Hydrogen its single electron will jump to a higher energy state until it releases it's own photon and returns to a lower state. My question is that what if a high energy gamma ray hits the Hydrogen atom? The electron will fly a long...

Homework Statement The carbon-dioxide has nondegenerate vibrational energies εr=（h/2π）ω(r+1);r=0,1,2..., where ω=(1.26*10^14)s^-1. What is the contribution of these vibrational modes to the molar heat capacity of carbon-dioxide gas at T=400K? Homework Equations...

The question involves testing the Specific Heat Capacity of an aluminum block, using the equation: Q = m x Specific Heat Capacity x Change in Temperature. Two experiments are performed using the same power of the heater and the same mass of the object and a very similar change in...

Homework Statement The experiment was that we heated a beaker with water in it, and also a type of metal for around 5 minutes so that the metal becomes the same temperature as the water. We then dropped that heated metal into a stryofoam cup containing 189.10g of water in it. mass of...

Trying to determine the amount of energy required to heat a specific volume of air by a certain change in temperature. So far this is what I gotten. Vol: 10,000 cubic feet = 283.17 m^3 Orig Temp: 0C (32F) Final Temp: 21.1C (70F) deltaT: 21.1 K or C Density of air @ 0C: 1.293 kg/m^3 Cp...

Homework Statement If the cell capacity of a cell is 3,5A.h; calculate the number of electrons that flow through the cell in 30 minutes. Homework Equations Q= I.t The Attempt at a Solution Q= I.t = 3.5x(1800) = 6300C 6300/(1.6 x 10^-19) = 3.94 x 10^22 electrons

Hi, I just did a specific heat capacity test using a calorimeter, and the specific heat capacity I found (using heat gained = heat lost) is less than the real value. The problem is, I expected it to be more. I mean heat will be lost through the calorimeter, meaning that a greater amount of...

Hi there! So I'm aware that the phonon contribution is proportional to T^3 and for electrons it is T (this is for metals where the first result comes from the Debye model). I was wondering where the electron contribution is derived from and why it is such a low dependence.

When using the equipartition theorem to derive the heat capacity of an ideal gas, you have \left\langle H \right\rangle=\left\langle \frac{1}{2}m\left(v^{2}_{x}+v^{2}_{y}+v^{2}_{z} \right) \right\rangle and each degree of freedom contributes 1/2 kT to the total energy and 1/2 k to the total...

Homework Statement The cream is kept at 5 ºC in the lorries. It is pumped into silos, where it is pre-heated before being pasteurized. The silos are jacketed, and hot water is pumped through the jacket. Assuming no losses, if 300 kg of water at 90ºC enters the jacket and exits at 60 ºC...

I was in taught howw to proves the shannons capacity formula using by takng into conideration a n-hyperspace of uncertanity where the noise resides. It more like the geomteric proof of Shannon formula c = b*log(1+s/n) I have two problems 1) he modeled signals like a round circle and noise...

Hello, Can anyone explain to me what wire guages are? It just says its a measurement of how large a wire is and how much electric current in can safley handle. Can anyone give more insight? Also, if I want to power something that requires 100watts what size of a gauge should i use and why...

Homework Statement Just wanted to find some clarity regarding this subject. In my textbook, it states that Q = nCvdT for constant volume and Q = nCpdT for constant pressure. However, one of the TA's in my classes were telling us how dU = nCpdT for constant pressure and dU = nCvdT for...

Homework Statement In the temperature range from 60 K to 80 K, a certain amount of liquid has a temperature dependent heat capacity that is given by Cp = 20 J K−1 + T × 0.5 J K−2. Determine the entropy change resulting from heating this sample from 60 K to 80 K. Homework Equations...

Homework Statement So basically we're given a capacitor, or 2 metal plates, which has the capacity of 400 pikofarads (4*10^-10 F), a voltage of 200 V, and the distance between the two plates is 2 mm (2*10^-3 m). a) Find the charge of a plate. b) The strength of the electric field. c)...

Homework Statement I'm needing to write a program for thermodynamics, but before I can write the program, I need to find formulas for the heat capacity of a few substances: Al, Fe, BaTiO3, and Polyethylene. Ideally, I'm looking for equations that explain this behavior between 298K and 600K...

Homework Statement At 25C Cu metal (at. wt. 63.54 g/mol) has a molar heat capacity of 24.4 J/molK. The density of Cu is 8.949g/cm^3 at 0C and 8.904 g/cm^3 at 100C. Assuming that Cp is temperature independent, calculate Q, W, deltaU and deltaH when 100grams of Cu metal are heated from 0C to...

I'm fascinated with physics and probably know at least the nature of any effect or object in classical physics, but um... I have never in any textbook or article seen mention of what determines the specific heat capacity of a given substance. Which is kinda peculiar and confusing at the same...

Homework Statement A television picture is composed of approximately 300,000 individual picture elements (pixels), each of which can attain ten different and distinguishable brightness levels (such as black and shades of gray) for proper contrast. If for any picture element, the probability...

Hi Everyone :smile: I have to create an experiment for my assignment in Physics. I've chosen to do something about Specific Heat Capacity. A boy in my class is also doing SHC so I wanted to make mine a little different from his. I've just recently joined physics (never done it before)...

Homework Statement Two identical conducting spheres of radii "a" are kept in contact. Find the capacity of the system Homework Equations C=Q/V The Attempt at a Solution Since the two spheres are kept in contact so they are at the same potential.So we need to find out this potential so as...

I am trying to work out the heat capacity of a body-centered cubic iron lattice using stat.mech., but am having some trouble. Firstly, I assumed that the iron atoms behaved as harmonic occilators, not taking electronic or nuclear spin into account. Is this a good or bad approximation? Then...

when working this out, is it just Cv + Cp? giving 4nR? thanks

. How a field request capacity of a channel?

I think its time we seriously educated people about food. Its now been proven again and again that natural fats and carbohydrates are not the problem with obesity and weight issues. It is the consumption of man made versions of these products. Just by cutting out foods that contain processed...

Homework Statement A 300-gal capacity tank contains a solution of 200 gals of water and 50 lbs of salt. A solution containing 3 lbs of salt per gallon is allowed to flow into the tank at the rate of 4gal/min. The mixture flows from the tank at the rate of 4 gal/min. The mixture flows from the...

Initial Nodal Temperatures Please Help, I am learning how to do 2-D time-dependent linear heat conduction for Finite Elements, and am progressing but have a question with nodal heat values. I am using the explicit Euler Forward Difference algorithm and as such need to set initial nodal...

Homework Statement The temperature at the top of a popular waterfall is 22.0 degrees celcius. The temperature at its base, 210 m lower, is 22.5 degrees celcius. 1)Caluclate the specific heat capacity of the water. 2) If the waterfall was twice as tall, determine by how much the water...

I would like to increase the maximum current that a PWM signal from a microcontroller can source/sink from +-25mA to +-500mA. The output should have the same peak-to-peak voltage (0 to 3.3V) and should not be inverted (i.e. follows the input). The PWM frequency is ~30kHz. I have looked...

Hi! I've been reading up on FDMA and CDMA and wondering why is it that in CDMA, each message is spread over the entire bandwidth allotted instead of using a single range of frequencies (say, alloted to one user in FDMA), for several users (by assigning a unique code to each of them)? Why...

Homework Statement To determine a formula that can be used to determine the lifting capacity of an electromagnet/magnet through a known air gap. Homework Equations Weight= (magnetomotive force)/reluctance The Attempt at a Solution From the experiment the following general...

Hello everyone, In anameia related to iron, plasma tranferring increases and iron decreases. How does this increase the total iron binding capacity of the enzyme. If I draw a sample of blood, there would be some transferrin enzymes in excess lowering iron binding capacity right? Thanks :smile:

Hello, I want to study transparent alumina and zirconia and I wonder if they have the same conductivity and heat capacity than the dense and opaque materials ? As I can only find datas for the common materials (e.g. dense opaque ones) it would be great! My point of view is that the...

Homework Statement 3.00 kg of molten lead is allowed to cool until is has solidified. It is found that the temperature of the lead falls from 605 K to 600 K in 10 s, remains constant at 600K for 300 s, and then falls to 595 K in a further 8.4 s. Assuming that the loss of heat energy remains...

I'm working from Feynman's definition of internal energy for the Debye theory of heat capacity. I'm trying to use that to derive the normal definition of heat capacity that I've seen. But I'm running into a problem. Note, in the following V_0 is frequency, whereas V is volume (that's how Feynman...