Why Power in a circuit is Zero , in which Current and Voltage are 90 Degree out of phase?

as P=I*VCos< so if the angle is90 so cos90 is equal to zero so the power will be zero

There are three different types of power.

When Cos90 is0, Sin90 will be maximum which is reactive power.

So Power is there but it is in different direction.

Because of the fact the Power in an AC circuit is P=VI cos φ and since Voltage and current are90 degree out of phase. cos (90) =0

P = VI cos (90) =0

Power in3 Phase circuit given as P=sqrt (3)*V*I*Cos(pi), where pi is angle between voltage & current in degree. so now according to your question angle= degree so Cos degree=0 so power =0.hope this the satisfying answer for your question? 

Due to power factor.  Which is zero in this case.