Final answer:
The number of spectral lines in the spectrum formed when the electron in the atom excites to the fourth orbit and jumps back to lower energy levels is 12.
Step-by-step explanation:
In the Bohr model of the atom, when an electron jumps back to a lower energy level, it emits a photon of light. Each electron transition corresponds to the emission of a specific wavelength of light. The number of spectral lines in the spectrum formed when the electron in the atom excites to the fourth orbit and jumps back to lower energy levels can be determined using the formula:
# of spectral lines = n2 - n = (42 - 4)
= 16 - 4
= 12
Therefore, the correct answer is (c) 12.