Chapter 7: Q 7.37 (page 293)
Prove that the peak of the Planck spectrum is at x = 2.82.
Short Answer
Hence proved that plank's spectrum is at x = 2.82.
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Chapter 7: Q 7.37 (page 293)
Prove that the peak of the Planck spectrum is at x = 2.82.
Hence proved that plank's spectrum is at x = 2.82.
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Each atom in a chunk of copper contributes one conduction electron. Look up the density and atomic mass of copper, and calculate the Fermi energy, the Fermi temperature, the degeneracy pressure, and the contribution of the degeneracy pressure to the bulk modulus. Is room temperature sufficiently low to treat this system as a degenerate electron gas?
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Evaluate the integral in equation numerically, to confirm the value quoted in the text.
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Consider a Bose gas confined in an isotropic harmonic trap, as in the previous problem. For this system, because the energy level structure is much simpler than that of a three-dimensional box, it is feasible to carry out the sum in equation 7.121 numerically, without approximating it as an integral.*
(a) Write equation 7.121 for this system as a sum over energy levels, taking degeneracy into account. Replace with the dimensionless variables .
(b) Program a computer to calculate this sum for any given values of . Show that, for , equation 7.121 is satisfied at provided that . (Hint: You'll need to include approximately the first 200 energy levels in the sum.)
(c) For the same parameters as in part (b), plot the number of particles in each energy level as a function of energy.
(d) Now reduce to 14 , and adjust the value of until the sum again equals 2000. Plot the number of particles as a function of energy.
(e) Repeat part (d) for . You should find that the required value of increases toward zero but never quite reaches it. Discuss the results in some detail.
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