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?

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. (b) Explain why pure silicon is opaque.

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?

The unstable isotope 40K is used for dating rock samples. Its half-life is 1.28x10^9 y. (a) How many decays occur per second in a sample containing 1.63x10^-6 g of 40K? (b) What is the activity of the sample in curies?