Exam 33: The Nature and Propagation of Light

Semiconductors: The energy gap between the valence and conduction bands in a certain semiconductor is 1.25 eV. What is the threshold wavelength for optical absorption in this substance? (c = 3.00 × 10⁸ m/s, 1 eV = 1.60 × 10^-19 J, h = 6.626 × 10^-34 J ∙ s)

Molecular vibration: A vibrating diatomic molecule in its ground state has energy E. What is the energy of the same molecule in its second EXCITED state?

Molecular rotation: A rotating diatomic molecule in its l = 1 quantum state has energy E. What is the energy of the same molecule in its l = 2 quantum state?

Free-electron theory of metals: For a solid in which the occupation of the energy states is given by the Fermi-Dirac distribution, the probability that a certain state is occupied at a temperature T₀ is 0.70. If the temperature is doubled to 2T₀, what is the probability that the same state is occupied? Assume that the Fermi energy does not change with temperature.

Free-electron theory of metals: If a metal had a Fermi level (energy) of 5.0 eV, what would be the average energy of the electrons at 0 K?

Molecular rotation: A diatomic molecule has 2.6 × 10^-5 eV of rotational energy in the l = 2 quantum state. What is its rotational energy in the l = 1 quantum state?

Molecular rotation: A certain molecule has 2.00 eV of rotational energy in the l = 1 state. In the l = 4 state, what would its rotational energy be?

Molecular bonds: Covalent bonding is due to

Semiconductors: In a p-type semiconductor, a hole is

Density of states: Approximately how many states in the range from 5.0 eV to 5.2 eV are there in a copper bar of volume 5.3 cm³? (h = 6.626 × 10^-34 J ∙ s, ħ = 1.055 × 10^-34 J ∙ s, m_el = 9.11 × 10^-31 kg, 1 eV = 1.60 × 10^-19 J)

Molecular vibration: A vibrating diatomic molecule has vibrational quantum number n. The energy DIFFERENCE between adjacent energy levels