Question

Why bohr's orbits called stationary states

Answer 1

Energies in which electrons revolve in a shell is fixed. Hence, bhor's orbit are called stationary states.

Answer 2

bohr's orbits are called as stationary states because as we know that if an object moves in circular path it will lose energy but, according to bohr electrons which is moving in the circular path does not lose energy.if electrons lose energy they will fall into nucleus and get burnt.