An electron is trapped on the end of a spring with spring constant k. What are all of the possible values of k such that the longest wavelength light that can excite the electron from its ground state to any excited state is visible light. (Note: our textbook identifies the range of visible light to be between 400 nm and 700 nm. See, for example, Table 33.1.) Your answer should be a numeric range. Make sure that the dimensions of your answer correspond to those of a spring constant, but you may use any units you want