What is meant by wattless component of current ?

The current in a.c circuit is wattless if average power consumed is zero. if $\mathrm{\varphi }$ is the phase difference between a.c emf and current in a circuit, then the component of current$\text{ (i.e. }\left.{\mathrm{I}}_{\mathrm{o}}\sin \mathrm{\Phi }\right)$ is called wattless current.