Questions from Modern Physics

Q: The spacing of adjacent atoms in a crystal of sodium chloride is

The spacing of adjacent atoms in a crystal of sodium chloride is 0.282 nm. The mass of a sodium atom is 3.82 * 10-26 kg, and the mass of a chlorine atom is 5.89 * 10-26 kg. Calculate the density of so...

Q: Potassium bromide (KBr) has a density of 2.75

Potassium bromide (KBr) has a density of 2.75 * 103 kg/m3 and the same crystal structure as NaCl. The mass of a potassium atom is 6.49 * 10-26 kg, and the mass of a bromine atom is 1.33 * 10-25 kg. a...

Q: The maximum wavelength of light that a certain silicon photocell can detect

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

Q: The gap between valence and conduction bands in diamond is 5.

The gap between valence and conduction bands in diamond is 5.47 eV. a. What is the maximum wavelength of a photon that can excite an electron from the top of the valence band into the conduction band...

Q: The gap between valence and conduction bands in silicon is 1.

The gap between valence and conduction bands in silicon is 1.12 eV. A nickel nucleus in an excited state emits a gamma ray photon with wavelength 9.31 * 10-4 nm. How many electrons can be excited from...

Q: a. Calculate the electric potential energy for a K+ ion

a. Calculate the electric potential energy for a K+ ion and a Br- ion separated by a distance of 0.29 nm, the equilibrium separation in the KBr molecule. Treat the ions as point charges. b. The ioniz...

Q: Calculate vrms for free electrons with average kinetic energy 3/2

Calculate vrms for free electrons with average kinetic energy 3/2 kT at a temperature of 300 K. How does your result compare to the speed of an electron with a kinetic energy equal to the Fermi energy...

Q: Particle A is described by the wave function Ψ(x,

Particle A is described by the wave function Ψ(x, y, z). Particle B is described by the wave function Ψ(x, y, z)eiɸ, where ɸ is a real constant. How does the probability of finding particle A within a...

Q: Calculate the density of states g(E) for the free

Calculate the density of states g(E) for the free­electron model of a metal if E = 7.0 eV and V = 1.0 cm3. Express your answer in units of states per electron volt.

Q: The Fermi energy of sodium is 3.23 eV.

The Fermi energy of sodium is 3.23 eV. a. Find the average energy Eav of the electrons at absolute zero. b. What is the speed of an electron that has energy Eav? c. At what Kelvin temperature T is...