What is Fermi energy level ?

What is donor energy level?Explain.

What are energy levels or shells ?

What is the wavelength of light emitted when the electron in hydrogen atom undergoes transition from an energy level with n = 6 to an energy level with n = 3 ?

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes trnsition from an energy level with n = 4 to an energy level with n = 2 ?

Calculate the ratio of energies of photons produced due to transition of electron of hydrogen atom from its, Second permitted energy level to the first level? 2. The highest permitted energy levels to first permitted level?

When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom.