Questions from Modern Physics

Q: Van der Waals bonds occur in many molecules, but hydrogen bonds

Van der Waals bonds occur in many molecules, but hydrogen bonds occur only with materials that contain hydrogen. Why is this type of bond unique to hydrogen?

Q: Individual atoms have discrete energy levels, but certain solids (which

Individual atoms have discrete energy levels, but certain solids (which are made up of only individual atoms) show energy bands and gaps. What causes the solids to behave so differently from the atoms...

Q: Ionic crystals are often transparent, whereas metallic crystals are always opaque

Ionic crystals are often transparent, whereas metallic crystals are always opaque. Why?

Q: The bonding of gallium arsenide (GaAs) is said to be

The bonding of gallium arsenide (GaAs) is said to be 31% ionic and 69% covalent. Explain.

Q: A student asserts that silicon and germanium become good insulators at very

A student asserts that silicon and germanium become good insulators at very low temperatures and good conductors at very high temperatures. Do you agree? Explain your reasoning.

Q: The electrical conductivities of most metals decrease gradually with increasing temperature,

The electrical conductivities of most metals decrease gradually with increasing temperature, but the intrinsic conductivity of semiconductors always increases rapidly with increasing temperature. What...

Q: The saturation current IS for a p-n junction, Eq

The saturation current IS for a p-n junction, Eq. (42.22), depends strongly on temperature. Explain why. From Eq. (42.22):

Q: Why does tunneling limit the miniaturization of MOSFETs?

Why does tunneling limit the miniaturization of MOSFETs?

Q: The moment of inertia for an axis through the center of mass

The moment of inertia for an axis through the center of mass of a diatomic molecule calculated from the wavelength emitted in an l = 19 l = 18 transition is different from the moment of inerti...

Q: Analysis of the photon absorption spectrum of a diatomic molecule shows that

Analysis of the photon absorption spectrum of a diatomic molecule shows that the vibrational energy levels for small values of n are very nearly equally spaced but the levels for large n are not equal...