Internal Definition and 993 Threads

In Total Internal Reflection, the beam can still lose some energy as it reflects off the boundary of the medium it is within. This isn't covered under the Fresnel equations. The energy loss is probably lost in the form of evanescent waves. I tried searching for the formulae describing the...

I'm watching a lecture introduction internal energy and in it, the lecturer states the following for some system: E_{internal} = E_{translational} + E_{vibrational} + E_{rotational} + E_{other} where ## E_{other} ## could be chemical energy, magnetic energy, electrostatic energy etc. Then...

Homework Statement Calculate the magnitudes and directions of the currents in each of the 3 resistors in the circuit above, if... (a) ...both batteries have zero internal resistance. (b) ...each battery has an internal resistance of 1.0 Ω. Homework Equations I1 = I2 + I3 (Node Law)The...

Homework Statement Match the following Given : Processes do not include chemical reactions. Assume CP,m and CV,m are independent of temperature for given substance and consider only pressure-volume work in given all processes. Homework Equations ΔU = Q - W ΔH = ΔU +...

Hi. I have been trying to solve this problem that has been keeping me up at night for a coupe weeks at least. If anyone can help me, I would be greatly appreciated. Hot air enters a cylindrical duct. The duct has some R-value and radiation and convection is being accounted for on the outside...

Homework Statement Three identical batteries are first connected in parallel to a resistor. The power dissipated by the resistor is measured to be P. After that, the batteries are connected to the same resistor in series and the dissipated power is measured to be 4P (four times larger than for...

I've been wondering about this question for some time now. There are the following two contributors: ~~~~~~~~~~~~~~ 1. Heat left over from the planet's initial formation. In the early 19th century Lord Kelvin estimated the temperature based on a homogenous sphere of uniform initial temperature...

Hi. There is a problem that I have been working on and I seem to be getting somewhat unrealistic results. Can anyone critique my modeling method? Problem: Heated air enters a duct of length L at temp T_h. The outside of the thin walled duct will have convection and radiation both being...

In measuring the internal resistance of a power supply, why is a resistor with low resistance used?

Homework Statement If water vapor is assumed to be a perfect gas, molar enthalpy change for vaporization of 1 mol of water at 1 bar and 100 C is 41 kJ/mol . Calculate the internal energy, when 1 mol of water is vaporized at 1 bar pressure and 100 C. Homework Equations $$\Delta U = \Delta H =...

I'm reading a book on thermal physics and the author says this: "In general, the internal energy will be a function of temperature and volume, so that we can write U =U(T,V) " How do we know this intuitively and how do we know that internal energy is not a function of pressure as well?

From what I understand, the molecules/atoms that make up an object are in constant, random motion. Do electromagnetic forces cause this motion or what is the cause of it? If so, why would net electromagnetic forces exist between "neutral" atoms?

Homework Statement An automobile battery has a terminal voltage of 12.8 V with no load. When the starting motor (which draws 90A) is running, the terminal voltage drops to 11.0 V. What is the internal resistance of the battery? Homework Equations V= EMF- Ir The Attempt at a Solution I think...

Homework Statement Question attached. I want to check what values of WT I should use. Homework Equations Effective dose = WT*WR*WT,R The Attempt at a Solution For the neutron whole-body dose I have WT = 1. For the ingested 90Sr and 131I, I also have WT = 1. Are these correct or does...

hi, I met a problem about heat transfer in cylinder, if you can help, I will appreciate it. The question is simple. I want to know the transient heat distribution in a cylinder with internal heating(constant temperature not constant flux). The boundary conditions comprises two constant...

Homework Statement Re-arranging the equations of potential (internal) energy in a monoatomic gas, i get this differential equation: \gamma (dV/V ) + (dP/P) = 0. where V is volume and P is pressure. I have to integrate it. Homework EquationsThe Attempt at a Solution I tried, but i wasnt able...

Homework Statement Homework Equations F= ma P= F/A The Attempt at a Solution a). Assuming the piston is in equilibrium, I'm applying Newton's second law F=ma=0 Equals zero because it is not moving Note: P=F/A which I rearrange to solve for the force for F= PA. This represents the...

Hello. I am starting to learn about thermodynamics. (i'm going to use lower case "d" for delta) Energy is neither created nor destroyed. So dU = 0 for the universe as a whole. If the universe is constantly expanding, then it must be doing work on the vacuum around it, right? So W is a...

Hello I am trying to read data from one activity, save it to a file... and when open another activity I will be able to read that file(by opening it). I searched for tutorials, all they are showing on the same activity. I figured out how the code works.. but I'm not able to understand what will...

I have question regarding the (W = ∫Pdv) formula for the work done during the expansion of an ideal gas and the change in internal energy during the process. If we were to have a gas enclosed inside an insulated cylinder with a movable piston at one end with cross sectional area "a", I...

Homework Statement The IQE is defined as (photons emitted from active region ##s^{-1}##) / electrons injected across the junction. Derive an expression for this quantity, then find the injected electron concentration ##n## which maximises it. Homework EquationsThe Attempt at a Solution We've...

Homework Statement Let ##\{G_i \mid i \in I\}## be a family of groups, then ##\prod^w G_i##, the external weak direct product, is the internal weak direct product of the subgroups ##\{i_k(G_k) \mid k \in I\}##, where ##i_k : G_k \to \prod G_i## is the canonical embedding. Homework...

Homework Statement Let ##H, K, N## be nontrivial normal subgroups of a group ##G## and suppose that ##G = H \times K##. Prove that ##N## is in the center of ##G## or ##N## intersects one of ##H,K## nontrivially Homework EquationsThe Attempt at a Solution I presume that ##G = H \times K##...

Homework Statement since specific heat c changes with temperature, but its treated as a constant in the heat formula, so that means that heat formula Q=mc(T2-T1) is just an approximation? correct? I see some texts define heat as Heat, q, is thermal energy transferred from a hotter system to a...

since specific heat c changes with temperature, but its treated as a constant in the heat formula, so that means that heat formula Q=mc(T2-T1) is just an approximation? correct? I see some texts define heat as Heat, q, is thermal energy transferred from a hotter system to a cooler system that...

Homework Statement Homework Equations The Attempt at a Solution v2=vf+x*vfg x =(0.4458-0.001067)/(0.71813-0.001067) =0.61973 u2=uf+x*ufg =535.08+0.61973*(2001.8-535.08) =1444.05kJ/kg ==> far different from solution! whats wrong with my attempt? thanks

Assuming all gases in the combustion reaction of benzoic acid (C6H5COOH) behave ideally, what is the "exact" change in internal energy? The context in which this question is being asked is after a calorimetry experiment. For all the intents and purposes of calorimetry, the change in internal...

The internal energy of monoatomic ideal gas is due to the kinetic energy of the molecules. Using Boltzmann Maxwell distribution, it is calculated that the kinetic energy due to translational motion of gas molecules of an ideal gas depends only on the temperature. In case of monoatomic gas, since...

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1. The problem statement I did a laboratory work in which I had to find power and internal resistance. I used an ordinary battery so it's closed circuit. I did all tasks except writing a hypothesis and conclusion I can't really think of it. I don't know what to write since I just measure using...

Homework Statement Today I did a laboratory work in which I had to find power and internal resistance. I used an ordinary battery so it's closed circuit. I did all tasks except writing a hypothesis and conclusion I can't really think of it. I don't know what to write since I just measure using...

Homework Statement Suppose I have a system which contains two bodies m1 and m2 with initial velocities v1 and v2 , respecitvely. they hurl toward each other and make an inelastic collision. such that they are now one body of mass m1 + m2 I know that the difference in momentum is...

how total internal reflection of light takes place in terms of quantum world?

I'm having a difficult time understanding why the internal resistance of the EMF source is disregarded in this problem. 1. Homework Statement You are asked to determine the resistance per meter of a long piece of wire. You have a battery, a voltmeter, and an ammeter. You put the leads from the...

Homework Statement I'm having a hard time finding the reactions at the supports and the force exerted by the spring. Given: 20 lbs 25 lbs 35 lbs k = 200 lb/ft lo = 2.5 ft members are 4 ft longHomework Equations ΣM ∑Fy = 0 ∑Fx = 0 The Attempt at a Solution I tried solving for the reactions...

Homework Statement I measured a battery rated at 1.5V(ε) and get 0.9V out and want to calculate the internal resistance (r). So, I model the battery as an ideal voltage source and a resistor in parallel. I know the voltmeter has a resistance of 1kΩ (R). How do I calculate the internal...

Internal energy at a specific state can't be calculated but by kinetic theory of gases and law of equipartition of energy Average kinetic energy is directly proportional to temperature.And for an ideal gas internal energy is due to kinetic energy only for an ideal gas potential energy can be...

Homework Statement Two containers hold an ideal gas at the same temperature and pressure. Both containers hold the same type of gas but container B has twice the volume of container A. The internal energy of the gas in container B is (a) twice that for container A (b) the same as that for...

If rotational kinetic energy of a closed system decreases, another form of energy must increase for the conservation of energy of a closed system. We assume this system (a person in rotation) has these forms of energy: ΔE=ΔK (only rotational around an axis) + ΔUi (internal) + ΔEt (thermal) with...

On average, which has higher power to weight ratio between the two? So on average, if both weighed the same, which one is going to have more power?

Integral constant for internal energy of ionic liquid I have a question, and I will be really grateful if someone helps me. I have a polynomial equation for internal energy which I calculated by integration an equation of state formula, which is based on density. But, because I calculated this...

Integral constant for internal energy of ionic liquid I have a question, and I will be really grateful if someone helps me. I have a polynomial equation for internal energy which I calculated by integration an equation of state formula, which is based on density. But, because I calculated this...

if a cell is running down, there would be a constant drop in p.d. across the cell, does the internal resistance of the cell increase or decrease?

Hi, I've been reading about compressed air energy storage and keep coming across that in 300 bar containers the achievable energy is 0.1MJ/L. Is this 0.1MJ/L of the volume of the air it is compressed to or of the total L of air that was initially used? (E.g If 1500L is compressed to 300 bar...

Hey All, I have a plastic vessel fully filled filled with an incompressible fluid (Water), at some time this vessel is impacted and crushed on one side (say 5% of the initial volume is lost). Only, I know the volume isn't lost, the fluid (being incompressible) will exert pressure on all...

Hi everyone! 1. Homework Statement Given is a function for the internal energy: ##U(T,V)=Vu(T)## Asked is to derive the entropy balance equation. In order to do so i need to find the "isothermal and adiabatic compressibility": $$\kappa_{T}=-\frac{1}{V}\left(\frac{\partial V}{\partial...

Homework Statement In a potentiometer 99cm of wire of resistance 99ohms is connected with a battery of 50V and 1ohm internal resistance.Find emf of battery giving zero deflection for a length of 13cm. Homework Equations Sadly,the formula I know is only for ideal emfs,which states that: If two...

Homework Statement Please look at the below images which is the derivation of the relation between the internal energy of an ideal gas and the molar specific heat at constant volume. (Snaps taken from Fundamentals of Physics Textbook by David Halliday, Jearl Walker, and Robert Resnick) As...

Homework Statement A battery of emf 2V and internal resistance 0.1ohm is being charged with a current of 5 ampere. In what direction will the current flow inside the battery?What is the potential difference between the two terminals of the battery? Homework Equations If a battery of emf E and...

Hello, I have some trouble understanding the virial expansion of the ideal gas. 1. Homework Statement I have given the state equation: $$ pV = N k_b T \left(1+\frac{A\left(T\right)}{V}\right) $$Homework Equations [/B] and a hint how to calculate the caloric equation of state $$...