According to Bohr's atomic model,
∙ The electrons that revolve around the atomic nucleus lie in the concentric circular orbit at a certain distance from the nucleus.
∙ The energy of an electron is constant while it is in a particular circular orbit.
∙ When an electron jumps from an inner orbit to an outer orbit it absorbs energy equal to the difference of its energy level. Also, when it jumps from an outer orbit to an inner orbit it emits energy equal to the difference of its energy level.