# Why does kinetic energy of elecron on Bohr's orbit not change if zero of potential energy changes?

If zero of potential energy is not taken at infinity, total energy and potential energy of electron change but not kinetic energy. Why is that so?

If the sum of the potential and the kinetic energy would be constant, you wouldn't need to add or take energy to change the orbital. Since you have to add or take energy to change the orbital, the total energy of the particle has to change also.

The zero of PE is at infinity actually. A charge at rest would have 0 energy at infinity. That's why bounded states have negative energy. For the hydrogen atom, the electron at its fundamental level is $-13,6 eV$, negative because it would escape if it had 0 energy, just like any orbit.

Plus, KE depends on velocity, not on PE.