Internal Definition and 957 Threads

Homework Statement I'm having trouble with the following two problems: 1. A jar of tea is placed in the sunlight until it reaches an equilibrium temperature of 32*C. In an attempt to cool the liquid, which has a mass of .180kg, .112 kg of ice at 0*C is added. At the time at which the...

How internal reflection affect the performance of the thin film emissive display devices?

As the angle of incidence increases, the angle of refraction becomes larger. Should the underlined word be decreases? why? I think I've found a mistake in the book because according to snell's law of refraction n1sin(theta)1=n2 sin(theta)2 right? If n1>n2 then (theta)1<(theta)2 Wait, I...

While making calculations of FTIR/tunneling isn't that hard, I don't understand the phenomenon, and therefore there are some predictions I'm unable to make. So I have some questions (or it's probably just one). If you have a prism with refractive index n in vacuum, total internal reflection...

I am so lost with this question. Can anyone help? The internal energy of the gas in a gasoline engine's cylinder decreases by 176:7 J. If 67.0 J of work is done by the gas, how much energy is transferred as heat? Answer in units of J

Homework Statement Does the internal energy increase/decrease(U), quantity of heat released or supplied (Q), and work done by or on a system (W) when (a) water freezes to ice at constant temperature (b) ice melts to water at constant temperature (c) water evaporates at constant temperature...

Homework Statement Hi I've tried to solve this question but I keep getting stuck at a certain point, it probably very simple but any tips would be greatly appreciated The EMF of a cell is measured using a potentiometer and is found to be 1.51V. When a voltmeter, which has a resistance of...

Homework Statement In a circuit, two identical batteries with EMF of 22 V and internal resistance of 7 Ohm are placed in parallel to provide power to a load resistance of RL = 35 Ohms. What is the power transferred from the current to RL to heat the resistor? Homework Equations Is R(L)...

Hi everyone, We have an argument about gasoline combustion engine and diesel engine. Some say, the diesel engine is stronger than gasoline one. My idea is if the two engines are the same dimension, they must have the same power. Am I right or wrong. Thanks

I want to understand that why does the internal resistance of a cell/battery goes on increasing as the cell gets older. What happens inside the cell that causes the internal resistance to increase gradually? Thanks.

something strange happened to me recently, although this is just an anecdotal story, so i appreciate that what i thought had happened may not have been the case. anyway, I've noticed that if my alarm clock is consistently set to say, 7 AM, i will wake up roughly around that time even if I've...

1. The problem: A resistor has a resistance R, and a battery has an internal resistance r. When the resistor is connected across the battery, ten percent less power is dissipated in R than would be dissipated if the battery had no internal resistance. Find the ratio r/R. 2. Homework...

Homework Statement In the case of total internal reflection, show that the average rate of energy transport across the boundary is zero. Homework Equations None Provided The Attempt at a Solution All that I have come to is that I should use some form of the following method to find...

If I do 5 trials of measuring voltage and current of a circuit (with different resistors for each trial), how would I find the inner resistance of the power source?

A 575 kg satellite is in a circular orbit at an altitude of 550 km above the Earth's surface. Because of air friction, the satellite eventually falls to the Earth's surface, where it hits the ground with a speed of 2.10 km/s. How much energy was transformed to internal energy by means of...

Thermodynamics--work, heat, & internal energy Homework Statement When a system is taken from state i to state f along path iaf in Figure 18-41, Q = 60 cal and W = 20 cal. Along path ibf, Q = 51 cal. Fig. 18-41 (see attatched) (a) What is W along path ibf? (b) If W = -13 cal for the...

Homework Statement Does the molecule in the file attached have an enantiomer? Homework Equations The Attempt at a Solution I think I can draw an internal symmetry plane to divide the molecule into 2 equivalent parts, but then again, it doesn't seem quite right to me. Building...

How can I find the temperature of something if I'm give the internal energy(U), volume(V), and number of moles(N). I thought it'd just be pv = nrt but I am not sure what to do with the internal energy or how to use it with pressure. Thanks.

I'm currently studying A2 physics and I'm stumped on a particular question within a past paper involving internal energy of air. The question is as follows: Estimate the internal energy of the air in a room of volume 24m^3 at a temperature of about 20˚C. Assume that the air behaves as an...

Homework Statement Ok, you'll have to bare with me on this problem, this topic is not covered as part of my second level education. I think that ye do this in the US though. You are given a circuit containing a non-ideal power supply, an NTC resistor, an ammeter, a voltmeter, and a switch...

How do the angle of incidence relate mathematically with the angle of reflection after the critical angle, that is, in a TIR? Say we have a person standing at the bottom of a swimming pool, if we take the n for water as 1.33 and for air as 1, we get the critical angle of 48.75 degrees. When the...

Homework Statement The problem is that there are two , two-state paramagnets with Na = Nb (number of dipoles in each). uB = |kT|, energies of each dipole are + or - uB. Different internal energies to start, but they are brought together at thermal equilibrium and I need to find the average...

Does a battery really have any internal resistance? If it has then what's the origin of the resistance. We know that the electrons flow from negative to positive terminal of a battery. Do the electrons just end up releasing energy(such as heat) at the terminal/ or combines with the atoms of the...

The gold nucleus has an atomic mass of 197 with 79 protons and 118N and 79 electrons. The top quark has about the same mass, but no internal structure. It's just a particle with pure mass. Why would a structure of pure mass and nothing internal decay?

I have two different circuits and I need to work out the internal resistance of the cell. So far I have got to 0.8(5+r)=1.2(2.5+r) Where do I go from here?

Can anyone tell me if Internal\ Energy + Pressure * Volume equals heat, total energy, energy in transit? What if all energy is assumed to be in transit (heat all the way down)? Would that mean all energy is heat? I tend to think so for the following reason: In a "complete" system (with...

Hi, I am trying to do coursework on measuring the internal resistance of a solar cell. The light intensity on the solar cell is not going to change so the only thing that can be changed is the resistance as a variable resistor is used.But I am not sure how to find the internal resistance when I...

ok so DELTA U = Q - W Where U is internal energy, Q is heat transferred from or to the system and W is the work done BY the gas right? I always mix up U and Q, the concepts. My teacher said U depends entirely on temperature, is this right?? Also, if Q =ncDELTA T, isn't Q also dependent on...

URGENT! Please help! Circuit analysis (Thevenin voltage and internal resistance) Hi guys, I am really stuck on this portion of my lab and it's due tomorrow! Please help! I have two questions: The first deals with the diagram from the left of the attached picture. I have to prove that...

Ok, I must admit that I am becoming a bit confused about these concepts. I understand that enthalpy is u + Pv, and entropy has something to do with molecular randomness. I was fine until we started to solve for heat transfer when dealing with entropy and now I am confused, sometimes we use...

Are there any good sources anywhere for detailed info on how SPICE simulators work internally? I'm interested in learning more about how spice actually goes about its calculations, thanks.

Here is the question I need to solve: A battery has an emf E and an internal resistance r. When the battery is connected to a 25 ohm resistor, the current through the battery is 0.75 A. When the battery is connected to a 53 ohm resistor, the current is 0.45 A. Find the emf of battery and...

i recently heard that ups is designing and testing a hydraulic system to power a torque converter for an efficient delivery system i need to know the validity of the situation and the plausibility of it being run by an electrically powered motor.

I'm doing a few practicals at home this summer, and the one that is bugging me is about EMF. I have measured voltage and current at different resistances across a 4,5 V battery, and made a graph. But to find the emf, am I supposed to take the slope of the graph, or the gradient? Or is that the...

I need a little starter on this one...can't figure out how to do it(or even start it)...I'll work it, if I can get some help along the way... Two moles of an ideal gas at 20 deg C undergo a free adiabatic expansion from 2.0 liters to 66 liters. Then the gas is adiabatically compressed such...

Sir, I have a doubt. The internal energy U is a unique function of any state because change in U ___________. I think the answer is internal energy U is a unique function of any state because change in U does not depend upon path.U is a point function. But the given in book is " U depends...

Hi I wanted to know : - Most gases increase in temperature when they are compressed . Where does the energy for this come from . When a change of state from liquid to gases occurs is it accompanied by change in the internal energy of the liquid molecules ? Thanks a lot ..

Hi all, I'm stuck on a question, and I'm hoping you guys can help... Anyway, here it is: A J-shock in a Herbig-Haro object is propagating through neutral hydrogen gas at speed 100 kms-1. The gas has number density 107 m-3 and temperature 104 K. (d) The internal energy per unit mass of a...

These circuit questions seem to give me so many problems, this question in particular. What are the emf and internal resistance of the battery in the figure below? I have the answers, that emf is 9V and internal resistance is 0.5 ohms, however I'm having problems getting there. What...

Hi, I want to know, how we calacute the internal resister for the wire. what is the formula for it, and plase give me the constant for lead matel. to find the internal resister for it.

In this equation I r= E-V/V*R How would I find R? thanks in advance you your help.

A worker drives .5 kg spike into a rail tie with 2.50 kg hammer. Hits spike with 65 m/s. 1/3 kinetic energy converted to internal energy. Find increase in total internal energy. The problem I have having with this problem is that I don't know how to deal with the masses. I know PEi + KEi +...

hello I just realized I'm having some trouble figuring out the relationship between conservation of momentum and kinetic energy and internal energy in isolated system. We learned that total momentum gets conserved if two object collide in isolated system. But when learning about...

1. Cylinder contains 0.1 mol of ideal gas at a pressure of 2 atm and temperature of 300 K. The volume of the cylinder is 1.25 x 10^-3 m3. When the gas is heated from 300K to 350K, what is the change in internal energy of the gas? --->(I think the equation is Q=delta U + W but I don't know...

hello How does macroscopic kinetic energy KE get transformed into internal energy? Car bumps into trash can and small dent is made in the car.Dent is caused by force from trash can over certain distance (i.e. car gave part of its KE to trash can and trash can gave part of its KE back to...

hello First question-Internal energy W(I) of an ideal gas consists only of internal kinetic energy (thermal energy) W(KE). W(I) = W(KE) If at temperature T there are N molecules in an ideal gas,then total W(I) is W(I) = N*3/2*k*T We see from above formula that W(I) of ideal gas...

i figured out that Wac=21000J Wbc=0 Wab=91000J how do you find internal energy of U=Q+W?

hey so I'm doing this question on total internal reflection and have got myself totally lost here is the question: what is the smallest angle \theta(1) for which a laser beam will undergo TIR on the hypotenus of this glass prism? after reflecting off the hypotenuse at \theta(c) the...

Bremsstrahlung is the process in which an accelerated electron radiates and loses energy in the form of a photon(production of continuous X-rays). In photoelectric effect, an atom absorbs a photon and an electron from one of the shells is ejected. So, is it reasonable to regard X-ray...

Q) A 3 g bullet traveling at a speed of 400m/s enters a tree and exits the other side with a speed of 200 m/s. Where did the bullet's lost KE go, and what was the energy transferred? This is an example prob from my book which says: Change in KE+Change in Internal Energy=0 Hence, Change in...