Question

Why are Bohr orbits called stationary orbits?

Answer 1

An object moving in a circular orbit lost energy but according to Bohr electrons in orbitals do not lose energy. if they lose energy then they fall into the nucleus and hence atom will collapse. so electrons do not lose energy and the energies of orbits in which the electrons revolve are fixed. Hence, the energies of orbits in which the electrons revolve are fixed.