Can someone just answer these two questions

Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in the n=3 level to an orbital in the n=7 level.

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

Atoms contain subatomic particles called protons and neutrons. when these protons and neutrons spilt, a lot of energy is released