question_answer

An alternating current is given by \[l={{l}_{1}}\cos \omega t+{{l}_{2}}\sin \omega t\]. The root mean square current is given by:

A) \[\frac{\left( {{l}_{1}}+{{l}_{2}} \right)}{\sqrt{2}}\]                  

B) \[\frac{{{\left( {{l}_{1}}+{{l}_{2}} \right)}^{2}}}{2}\]

C) \[\sqrt{\frac{l_{1}^{2}+l_{2}^{2}}{2}}\]                   

D) \[\frac{\sqrt{l_{1}^{2}-l_{2}^{2}}}{2}\]