1. Why is it written that instead of considering N=N(μ) we consider μ= μ(N) but then for the partial derivative of S with respect to μ there is a chain rule that includes N as a function of μ? Where is the variable substitution reflected? this part is confusing to me.
2. What is the initial condition that is mentioned in a)? Is it that U and X are constant? does it refer to the thermodynamic limit?
Thanks for the questions. 1. I wrote "That is, instead of considering N = N(mu) we consider mu = mu(N)". This is indead misleading. It should rather say the opposite: "We then consider N = N(mu)". The idea is solving the differential equation for that function and then isolate mu as a function of N and the other variables, U and X which are kept fixed.
2. A general solution of the differential equation will be of the form
N(mu,U,X ) = N(mu0,U,X) + some function of mu,U,X which is zero at mu = mu0
I don't know yet the form of the solution. So it is hard to tell where to place the initial value. I.e. how to chose mu0.
Using the differential al work calculated on exercise 6.2: 1. How can we use the result to obtain DW for an ideal gas in a 3D container? What is the interpretation of the parameter "a" in that case. Solution. The differential of work calculated on exercise 6.2 is Here, d represents the dimension of the box. So The parameter a is the lenght, according to equation (67). Because we are working on 3 dimensions, a³=V . This might come from the definition of entropy*. 2. What do we get for DW for d=3 and n --> infinity? And how is this result related to the expected form DW = N k_B T dV/V? Solution. On the last expression we get DW for three dimensional case. Now, applying the limit on infinity, we expect that the differential of work would become on well potential one. So,
a) the code is: import numpy as np import matplotlib.pyplot as plt R=8.314 T=300 N=1 Va=1 Vb=2*Va g=5/3 Pa=N*R*T/Va Pb=Pa*(Va**g)/(Vb**g) l=np.arange(0,1,0.001) P1=l*Pb+(1-l)*Pa V1=l*Vb+(1-l)*Va V2=np.zeros(1000) P2=np.zeros(1000) for i in range (0,len(V2)): V2[i]=Vb-i/1000 P2[i]=Pa*(Va**g)/(V2[i]**g) c=P1[500]*(V1[500])**g V3=np.zeros(1000) P3=np.zeros(1000) for i in range (0,len(V2)): V3[i]=Vb-i/1000 P3[i]=c/(V3[i]**g) plt.plot(V1,P1) plt.plot(V2,P2) plt.plot(V3,P3) plt.plot(V1[500],P1[500],"o") plt.show() and the plot is: pd: i'm sorry i don't know how to pass some latex to html so i put it like images
Excuse me professor, I have two questions.
ResponderBorrar1. Why is it written that instead of considering N=N(μ) we consider μ= μ(N) but then for the partial derivative of S with respect to μ there is a chain rule that includes N as a function of μ? Where is the variable substitution reflected? this part is confusing to me.
2. What is the initial condition that is mentioned in a)? Is it that U and X are constant? does it refer to the thermodynamic limit?
Thanks for the questions.
ResponderBorrar1. I wrote "That is, instead of considering N = N(mu) we consider mu = mu(N)". This is indead misleading. It should rather say the opposite: "We then consider N = N(mu)". The idea is solving the differential equation for that function and then isolate mu as a function of N and the other variables, U and X which are kept fixed.
2. A general solution of the differential equation will be of the form
N(mu,U,X ) = N(mu0,U,X) + some function of mu,U,X which is zero at mu = mu0
I don't know yet the form of the solution. So it is hard to tell where to place the initial value. I.e. how to chose mu0.
Thank you for your answers professor!
Borrar