A photon is emitted by an atom when one of the atom's electrons -is removed from the atom. -shifts to a lower energy level. -shifts to a higher energy level. -collides with other electrons. -vanishes.Which of the following is true about Neils Bohr's "quantum leap"? -Electrons did not travel in the space between allowed orbits. -It could not explain the sharp lines in spectra (emission and absorption). -Electrons emitted radiation constantly. -Electrons could exist at any distance from the nucleus. -Electrons disappeared for minutes at a time