The wavelengths of light emitted by an excited atom are determined by the:
differences in energy between the excited states and ground state
addition of the energies of the excited states and ground state
multiplication of the energy of the excited states by the energy of the ground state
division of the energy of the excited states by the energy of the ground state

Explain using examples, what is simple harmonic motion and why it is an important area of study in physics.

Arotating space station is said to create “artificial gravity”—a loosely-defined term used for an acceleration that would be crudely similar to gravity. the outer wall of the rotating space station would become a floor for the astronauts, and centripetal acceleration supplied by the floor would allow astronauts to exercise and maintain muscle and bone strength more naturally than in non-rotating space environments. if the space station is 200 m in diameter, what angular velocity would produce an “artificial gravity” of 9.80 m/s^{2} 2 at the rim?

Need only answer if you think you know it