Internal Definition and 993 Threads

what is the differece between internal conversion electrons, electron capture and auger electons? i don't understand. The name suggests electron capture and internal conversion electrons are the same thing... but then when i look it up internal conversion electrons seem to be the same as auger...

Homework Statement To a source of current, one by one are added 2 resistances, first R1=1ohm, then R2=4ohm. In both cases, in the same period of time (t=t1=t2), the resistors give the same amount of heat (Q=Q1=Q2). Determine the internal resistance ("r" small r) of the electric source...

u denotes internal energy; v denotes specific volume; T denotes temperature.

Hi, I am a postgraduate environmental science student (NOT a mathematician!) struggling through some necessary maths. Any help with the following (which I suspect will be relatively straight foward) would be very much appreciated. Please ask questions if I have not made myself clear. Homework...

Hi, I was wondering if anone knew what an internal CD or DVD drive case is most commonly made of. I was hoping to use it to do some welding so am hoping it is steet but not sure. Cheers

Suppose you have the simplest type of black hole - time independent, no angular momentum or charge, Schwarzschild solution, then you modify the situation by adding a stationary mass outside the event horizon (I imagined lowering this slowly on an idealised string). The question is, does this...

Hi all! I have a quick question. In my Physical Chemistry textbook, the author states, "For a closed system in equilibrium, the internal energy (and any other state function) can be expressed as a function of temperature and volume." Can anyone explain just how that is true? I'm quite...

Homework Statement If only an external force can change the state of motion of a body, how can the internal force of the brakes bring a car to rest? The Attempt at a Solution I think that it may be because friction between brakes and wheels converts kinetic energy into heat. Or perhaps...

Hi, I'm taking a thermodynamics class and I'm stuck on how work relates to enthalpy and internal energy. Does work done by a system equal change in internal energy, change in enthalpy or does it depend on the situation? The question I'm stuck on asks for the work produced by a steam turbine...

Hello, first post here. I had a bit of an odd question that I can't get my head around, but I think is possible. Given the environment described in the picture, can you measure the amount of gas that is flowing from the hole in the box given that the pressure in the box has stabilized at a...

Hi I am a bit confused about the difference between Internal and External Descriptions of Systems. Didn't find any doc on web about this. A Little help needed :-). Thanks Salil

Homework Statement In a closed vessel there was some water vapor. After the water vapor dissociated, the temperature decreased by 10%, and the volume by 20%. Find the change in internal energy. (U{initial}-U{final})/U{initial} Homework Equations The Attempt at a Solution Let's...

Homework Statement "A car battery has an e.m.f. of 12V and an internal resistance of 0.04 Ω. The starter motor draws a current of 100A. a.) What is the terminal p.d. of the battery when the starter motor is in operation? b.) If the headlamps are rated at 12V, 36W, what is their resistance? c.)...

Homework Statement What happens to the internal energy of a system and its temperature when mechanical work is done on it? Homework Equations ΔU=Q-W The Attempt at a Solution First Law of Thermodynamics say:the change in internal energy of the system is equal to the heat added to the...

Sometimes in my book, a problem justifies ΔU=ΔH for a process, such as combustion in a bomb calorimeter, by saying that since the number of moles of gas doesn't change, they are equal. In other questions, the number of moles doesn't change (such as an irreversible expansion of a perfect gas)...

Hi, I am aware that due to the three body kinematics of beta decay, the energy spectrum of the electrons emitted is a continuous spectrum (where at one extreme the electron gets all of the disintegration energy and the antineutrino none, and the converse at the other extreme) I am doing an...

Homework Statement The question is as following: http://i56.tinypic.com/se547s.png Homework Equations W = F x distance or p d(v) . Potential energy : mgh , k.e : 1/2mv^2 The Attempt at a Solution Well I am stuck on part c, now I am aware that in adiabatic process Internal...

Homework Statement Enthalpy of formation of a mole of atomic hydrogen = 218kJ. Enthalpy changes when a mole of atomic hydrogen is formed by dissociating half a mole of molecular hydrogen. Calculate ΔU of the process of molecular hydrogen dissociation. Homework Equations ΔH = ΔU + Δ(PV)...

Homework Statement A liquid is irregularly stirred in a well-insulated container and thereby undergoes a rise in temperature. Regard the liquid as the system. (a) Has heat been transferred? How can you tell? (b) Has work been done? How can you tell? Why is it important that the stirring is...

A 6.0 V battery has an internal resistance r. The measured voltage (emf of the battery) is 6.0 V. When connected to a resistor R the terminal voltage is 5.9 V and the current is 0.18 A. I managed to get a) What is the internal resistance r of the battery? 0.556 ohm as well as b) What is...

I know, as a matter of fact, that the equivalent resistance of three identical cells in parallel is equal to the internal resistance devided by 3. When we are concerning simply 3 equal resistors in parallel, I know that the outcome resistance is what. But when it comes to three cells with...

Homework Statement Consider air in chemical equilibrium at 0.1 atm and T=4500 K. The chemical species are O2, O, N2, N (Ignore NO). Calculate the enthalpy and internal energy per unit mass of the mixture. Neglect electronic excitation in your calculations. K_{p,O_2}=12.19 atm...

Homework Statement A lamp is placed in the center at the bottom of a 2m deep swimming pool. The lamp emits light in all directions. Starting from a point directly above the lamp, a man in a canoe paddles until he no longer can see the lamp. How far did he paddle the canoe? Assume that the...

I have to prove that D4 cannot be the internal direct product of two of its proper subgroups.Please help.

U=q+w U is the total kinetic and potential energy of the system. H=U+PV Enthalpy is the internal energy of the system, plus how much energy it takes to set up the system. I don't understand how the PV term from enthalpy is not included in the internal energy. It seems like it would...

Homework Statement The Attempt at a Solution for part 1: i figured that this structure is not in static equilibrium. once load "P" is applied, the roller at "D" will function as a fulcrum and ABC will lift (make an angle with the horizontal). is that assumption correct...

Hi :) Uhh, this question is quite simple but I'm still confused between these two terms... Am I right to say that internal energy is the sum of kinetic energy and potential energy of all the particles in a system? Meaning the two factors are the number of particles, and the energy of each...

I have these two homework problems, as well as solutions. What I do not understand is why the solution for one is not the solution for the other. First problem: A sample consisting of 1.00 mol Ar is expanded isothermally at 0 deg Celc from 22.4 dm3 to 44.8 dm3 reversibly. Calculate q, w, delta...

hi all, im having trouble working out the internal forces in this question, i tried before and got stuck working out the forces at joint C. i have been to see my tutor however he is on holiday till after the deadline for this assignment. handy... i was working out the forces by the...

So, is the internal energy of a system always constant? I mean, if work done on the system is negative by convention. dU = dQ - pdV Then if work is done on the system, does that mean that it has to absorb heat to keep the internal energy constant? and if the system does work, it has to...

Can some one check my work, I'm not sure if I am understanding how internal energy heat and work are related. Work is defined to be positive if the system does work on the environment. Q=\Delta U +W I am showing if the process is positive, negative or 0. Also this is suppose to be an ideal gas

does the identity of molecules affect the internal energy, besides the temperature and volume?

If there is total internal reflection, does the angle of incidence always equal the angle of reflection? Thanks

Does total internal reflection occur if the refraction of light is passing from air into water? Thanks

Constant internal energy with volume change?? My book says that you can change the temperature of a substance at constant internal energy by changing only the volume. how can this happen? since the internal Energy E is this: \Delta E = q + w = q - P\DeltaV where q is heat, w is...

The internal Energy E is this: \Delta E = q + w = q - P\DeltaV where q is heat, w is work, and V is volume Phase changes occur when you change internal energy of the system, right? I am assuming that this means when you go from gas to liquid to solid, you must decrease the internal...

In magneto caloric effect, we see that when a substance in an adiabetic closure is exposed to external magnetic field, its temperature increases. But the internal energy of the substance has to be constant so this implies decrease in internal potential energy. However the application of magnetic...

Homework Statement Show that the change in internal energy of a simple system between states (V1, T1) and (V2, T2) is given by ∆U = \int^{T1}_{T2} C_v\ dT + \int^{V1}_{V2} T.\frac{\partial p}{\partial T}|_V - p \ dVHomework Equations dU=dQ-pdVThe Attempt at a Solution As U is a function of...

I am solving for the flow of heat on a resistor, say it has a cross-section in the x-z plane and is extended along the y-axis. Fick's Law with internal heating is simply \frac{\partial T}{\partial t}=A\nabla^{2}T+BQ My PDE text gives Q as power delivered per unit volume. So substituting in...

Homework Statement I am trying to find terminal voltage of the batteries in the circuit shown. Homework Equations V = IR The Attempt at a Solution The solution manual says that it's the battery voltage, v, minus the voltage drawn from the resistance v = I * R. I understand this. I do not...

Hi there. Here is the deal, today morning in my thermodynamic class we were making some exercises of stability, and then surged a question about internal energy. The thing is I thought that the internal energy should be always positive in sign. This doesn't mean that the variation must be...

Homework Statement Why is this false? "if systems A and B each consist of pure liquid water at 1 bar pressure and if TA>TB, then the internal energy of system A must be greater than that of B" Homework Equations The Attempt at a Solution It seems true to me. Could it be that B...

Homework Statement http://img217.imageshack.us/img217/654/circuit05.jpg Internal Resistance = 10 ohms (each) RL = 20 ohms R2 = 30 ohms R1 = 50 ohmsA) When the switch is open, calculate I B) When the switch is closed, calculate I Homework EquationsThe Attempt at a Solution First I'll try to...

What are the uses of mineral oils and self contained lubrication system in internal combustion engine? Please answer fast Its urgent

If we have N unique point masses, is it possible to use only internal forces (i.e. forces between each pair of masses) to reach any configuration of the points (modulo rotations and translations)? I assume this is well known, but don't know where to find a proof. Perhaps by induction from N=2...

Hi, Can someone explain the lubrication mechanism for a piston in a typical automotive internal combustion engine? If the walls in the piston chamber are coated with oil, the lubricant should also burn along with the petroleum during the combustion phase (leaving problematic residues), so, is...

Homework Statement A NON-monatomic gas expands from I to F in the Figure (Since it is not monatomic U=3/2nRT does not give you the internal energy, this only works for monatomic gases, instead you must use the first law). The energy added to the gas by heat is 424 J when the gas goes from I to...

Homework Statement See figure attached. Homework Equations The Attempt at a Solution Initially, \theta_{c} = 60^{o} n_{glass}sin\theta_{c} = n_{air} So, n_{glass} = \frac{n_{air}}{sin\theta_{c}} Now I would think that the incident angle from glass to air would be...

Homework Statement Assume ideal gas conditions. Cp=(7/2)R, Cv=(5/2)R 15 moles of airis contained in a cylinder and prevented from escaping by a frictionless piston initial conditions are 1.5 bar, gas volume 0.2m^3 final conditions required are 10 bar t 27 degrees celsius calculate...

Homework Statement Internal gravity waves are generated along the coast of Norway by the principal lunar semidiurnal surface tide (known as the M2 tide) of period 12.42 h. If the stratification frequency N is 2 x 10-3rad s-1, at which possible angles can the energy propagate with respect to...