The figure shown above shows the energy levels for a hydrogen atom. What is the energy of the photon emitted when the electron in a hydrogen atom drops from energy level E5 to energy level E2?

The energy of the photon emitted when the electron in a hydrogen atom drops from energy level E5 to energy level E2 is 2.85eV

Now, the energy of the ground state is - 13.6 eV.

the energy of the first state (n = 1) is - 3.39 eV.

the energy of the fifth state is - 0.54 eV.

Now, When an electron drops from higher to lower state, then energy difference is same as the energy of the photon emitted, is

= E5 - E2

= - 0.54 eV - (-3.39 eV)

= 2.85 eV