Why electrons don't fall to the nucleus?

Electrons are kept in the orbit around the nucleus by the electromagnetic force.

Explanation:

Electron revolves around the nucleus with a negative charge and the nucleus possesses a positive charge. The electrostatic force of attraction must pull the electrons into the nucleus but it's not that simple. There is a quantum mechanical feature that prevents the electrons to fall into the nucleus. This is described by the uncertainty equation between the position and momentum of the electron. The equation is represented as:

                                             

where,

              ħ= reduced Planck constant

This equation gives the limitation that an electron cannot fall into the nucleus.