A rubidium atom (m = 85 u) is at rest with one electron in an excited energy level. When the electron jumps to the ground state, the atom emits a photon of wavelength ⋋ = 780 nm. Determine the resulting (nonrelativistic) recoil speed v of the atom.

A rubidium atom (m = 85 u) is at rest with one electron in an excited energy level. When the electron jumps to the ground state, the atom emits a photon of wavelength ⋋ = 780 nm. The recoil speed sets the lower limit on the temperature to which an ideal gas of rubidium atoms can be cooled in a laser-based atom trap. Using the kinetic theory of gases (Chapter 18), estimate this “lowest achievable” temperature.

Which of the following samples contains particles with the lowest average $kinetic energy$?

Which of the following quantities measures the average kinetic energy of the particles in an ideal gas?$$

For an ideal gas, what is the average kinetic energy per molecule at temperature $T$?

Which of the following expressions correctly gives the average kinetic energy of a particle in an ideal gas at temperature $T$?

If the average kinetic energy of the atoms in an ideal gas is tripled, what is the new temperature in degrees Celsius if the initial temperature was $27$ °C?