Recent content by Shan K

See the attachment I can not understand how to derive equation (2.4) from (2.3). ##v_r## is the radial velocity of the gas in the accretion disk and ##c_s## is the sound speed.

I was studying about Accretion disks and found some difficulties regarding some concepts. My questions are 1. For an accretion disk, ## v_r<<c_s ## Why? 2. The conservation of mass equation is derived as, The mass in an annulus of radius ##\Delta r## is ##2\pi r \Delta r\Sigma ## and it is...

Thanks for the reply. But what I am saying is that for an ensemble, it consists of all the possible accessible microstate of a system. Then the time evolution of those elements will totally lie in that ensemble, isn't it right ? So in equilibrium how the elements can flow through the phase space ?

Hi, I was studying about the statistical ensemble theory and facing some problem to understand these concepts , I have understood that the ensemble is a collection of systems which are macroscopically identical but microscopically different . In some books they are called as systems with...

Thanks Phyzguy.

Thanks Chandra Prayaga for your reply. I have understood this concept but it doesn't prove the equivalence between 'Rotation' and 'any displacement' because in Goldstein they have assumed this equivalence first and then proved that for a rotation there must be an axis, through the proof of +1...

Hi, I am having some problems conceptualizing the Euler's Theorem. Any help will be greatly appreciated. In Goldstein's book the Euler's theorem is stated as 'Any displacement of a rigid body, whose one point remains fixed throughout, is a rotation about some axis', then he has proven that the...

But in the book by Resnick and Eisberg they have come to the wave function by considering the de broglie wave.In one hand they have said that a de Broglie wave cannot be a single wave because the phase and the particle velocity does not match and on the other hand they have said that the de...

I am not talking about absolute position but the position in my reference frame. And in classical physics we can define the position of a particle at each instant of time whether it is moving or not.

Hi, I was studying the solution of Schrödinger equation with no potential and found that the wave function is just a single plane wave eikx for movement of the particle in positive x direction. But when the phase velocity of a single wave is calculated it turns out to be less than the...

Hi, I have a question about the validity of Hiesenberg's principle when relativity is in action. Hiesenberg's principle tells us that simultaneous measurement of position and momentum can not be done accurately . But relativity tells us that simultaneity is relative , so simultaneous...

Ya. But it is not the whole description . We use dS=dQ/T for calculating the entropy change . But in this process the system goes from states (say) a to b but the surrounding is not it is going to some other states that's why when we take the system from b to a ,it able to recover its initial...

Thanks for the beautiful description . So you are saying that for every process the entropy change is fixed whether we take the reversible or irrevesible one. But for reversible paths thhe integral give us just the change in entropy for two states but for the irreversible paths we get less than...

Ok . But the book was saying that integral of dQ/T between two state points for reversible process is greater than the integral of dQ/T between the same two points in irreversible process . Then how can one define a proper entropy change for irreversible process . because it was defined as dS=...

I was studying 2nd law thermodynamics. In that context found the clausius's inequality saying closed integral of dQ/T <0 for irreversible process. And from the reversible process entropy was defined. And from that view they said that for irreversible process dS>dQ/T. Now when I saw some...