The maximum wavelength of light that a certain silicon photocell can detect is 1.11 mm. (b) Explain why pure silicon is opaque.

Pure germanium has a band gap of 0.67 eV. The Fermi energy is in the middle of the gap. (a) For temperatures of 250 K, 300 K, and 350 K, calculate the probability f(E) that a state at the bottom of the conduction band is occupied.

At the Fermi temperature T_F, E_F = kT_F (see Exercise 42.22). When T = T_F, what is the probability that a state with energy E = 2E_F is occupied?

CP Silver has a Fermi energy of 5.48 eV. Calculate the electron contribution to the molar heat capacity at constant volume of silver, CV, at 300 K. Express your result (a) as a multiple of R and

Calculate the density of states g(E) for the free-electron model of a metal if E = 7.0 eV and V = 1.0 cm^3 . Express your answer in units of states per electron volt.

The maximum wavelength of light that a certain silicon photocell can detect is 1.11 mm. (a) What is the energy gap (in electron volts) between the valence and conduction bands for this photocell?

The average kinetic energy of an ideal-gas atom or molecule is (3/2)kT, where T is the Kelvin temperature (Chapter 18). The rotational inertia of the H2 molecule is 4.6 * 10^-48 kg•m^2. What is the value of T for which (3/2)kT equals the energy separation between the l = 0 and l = 1 energy levels of H2? What does this tell you about the number of H2 molecules in the l = 1 level at room temperature?

CP The rotational energy levels of CO are calculated in Example 42.2. If the energy of the rotating molecule is described by the classical expression K = (1/2)Iω^2 , for the l = 1 level what are (b) the linear speed of each atom;

Measurements on a certain isotope tell you that the decay rate decreases from 8318 decays/min to 3091 decays/min in 4.00 days. What is the half-life of this isotope?