ATOMS — Physics STD 12 Science — Question

→Rutherford suggested that negatively charged electron revolves around the central nucleus just like the planets revolve around the sun.
→In a planetary system, the planets are held together by the gravitational force, while in an atom the electrons around the nucleus are held together by the Coulomb force.
• Limitations :
→An object which moves in a circular path is being constantly accelerated. This acceleration is called centripetal acceleration.
→According to classical electromagnetic theory, an accelerating charged particle emits radiation in the form of electromagnetic waves. Therefore the energy of an accelerating electron should continuously decrease.
→The electron would spiral inward and eventually fall into the nucleus. Thus, such an atom can not be stable.
→According to the classical electromagnetic theory, the frequency of the electromagnetic waves emitted by the revolving electrons is equal to the frequency of revolution.


→As the electrons spiral inwards, their angular velocities and their frequencies would change continuously, so the frequency of the light emitted also changes. Thus, they would emit a continuous spectrum, opposite to the line spectrum actually observed.