The higher power level band is called as the conduction band.
(i) It is also called as empty band of minimum energy.
(ii) This band is partially filled by the electrons.
(iii) In this band the electrons can gain energy from external electric field.
(iv) The electrons in the conduction band are known the free electrons. They are free to go anywhere within the volume of the solid.
(v) Current flows because of such electrons.