Bohr’s Model of Atom
Bohr combined the Rutherford model of atom with quantum ideas of radiation given by Plank.
He accepted Rutherford’s concept of nucleon atom model in which atom consists of positively charged nucleus but postulated that negatively charged particles known as electrons move around the nucleus in a few widely separated permitted orbits.
The orbit of an electron is fixed and does not radiate energy while moving in its fixed orbit known as stationary orbit. Thus in Bohr’s theory electrons can move only in some particular orbits of definite radii & not of all. When an electron jumps from higher stationary orbit to a lower stationary orbit, it radiates energy of definite frequency.