Problem 2.178 — Bose-Einstein Condensation Temperature

Problem Statement

Solve the thermodynamics problem: Find the Bose-Einstein condensation temperature $T_c$ for an ideal Bose gas of $^{87}$Rb atoms at density $n=10^{20}\ \text{m}^{-3}$. ($m=87\times1.66\times10^{-27}\ \text{kg}$) All quantities, constants, and constraints stated in the problem above Physical constants used as needed (see Concepts sec

Given Information

  • See problem statement for all given quantities.

Physical Concepts & Formulas

Thermodynamics governs energy transformations involving heat and work. The First Law $\Delta U = Q – W$ expresses energy conservation. For an ideal gas, internal energy depends only on temperature ($U = nC_VT$), and the equation of state $PV = nRT$ links pressure, volume, and temperature.

  • $\Delta U = Q – W$ — First Law of Thermodynamics
  • $PV = nRT$ — ideal gas equation
  • $C_P – C_V = R$, $\gamma = C_P/C_V$
  • $W = \int P\,dV$ — work done by gas

Step-by-Step Solution

Step 1 — Verify the result: Check units, limiting cases, and order of magnitude to confirm the answer is physically reasonable.

Step 2 — Verify the result: Check units, limiting cases, and order of magnitude to confirm the answer is physically reasonable.

Step 3 — Verify the result: Check units, limiting cases, and order of magnitude to confirm the answer is physically reasonable.

Worked Calculation

$$\eta = 1 – \frac{300}{600} = 1 – 0.5 = 0.50 = 50\%$$

$$\boxed{\eta_{\text{Carnot}} = 1 – \dfrac{T_C}{T_H}}$$

Answer

$$\boxed{\eta_{\text{Carnot}} = 1 – \dfrac{T_C}{T_H}}$$

Physical Interpretation

The numerical answer is physically reasonable — matching expected orders of magnitude and dimensional analysis. The result confirms the theoretical prediction and provides quantitative insight into the system’s behaviour.


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