(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A system consists of N pairs of non-interacting, spin 1/2 particles with magnetic moment [tex]\mu[/tex]. It is initially immersed in a uniform magnetic field [tex]H_{i}[/tex] while it is in thermal equilibrium with a reservoir at temperature [tex]T_{i}[/tex]. While remaining in thermal equilibrium with the reservoir, the magnetic field increased to a value of [tex]H_{f}[/tex]. At this point the system is isolated from the reservoir and the magnetic field returns adiabatically to [tex]H_{i}[/tex]. The system is then brought into thermal equilibrium with a second reservoir at temperature [tex]T_{f}[/tex].

(A) How much work is done on the system by the magnetic field?

(B) How much heat is transferred between the two reservoirs?

2. Relevant equations

[tex] U_{total}=N \mu H [/tex]

[tex] \delta U = Q + W [/tex]

3. The attempt at a solution

(A) Magnetic fields can't do work, so [tex]W=0[/tex].

(B) Recall relevant equations, so [tex] N \mu H = Q[/tex].

This seems like it, but I don't think it is. The temperature doesn't play a role. Does it mean the additional heat transferred to the solution in (B) is the change in energy due to temperature (e.g. [tex] \delta U = n R \delta T [/tex]?

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# Homework Help: Heat Transfer Between Reservoirs due to Magnetic Fields

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