Assertion (A): Electrons in the atom are held due to coulomb forces. 

Reason(R):  The atom is stable only because the centripetal force due to Coulomb's law is balanced by the centrifugal force.

A is true but R is false

According to postulates of Bohr's atom model, the electron revolve round the nucleus in fixed orbit of definite radii. As long as the electron is in a certain orbits it does not radiate any energy.