Question

If a current I given by I_O sin[ωt – (π/2)] flows in an ac circuit across which an ac potential of E = E_Osinωt has been applied, then the power consumption p in the circuit will be, 

(a) P = [{E₀I₀}/(√2)] 

(b) P = √2 E₀I₀ 

(c) P = [{E₀I₀}/(2)] 

(d) P = 0

Answer 1

The correct option (d) P = 0

Explanation:

I = I_O sin (ωt – {π/2})

E = E₀ sin ωt

Now power consumed = P = EI cos θ

 θ = angle or phase difference between E & I

here θ = 90°

∴ P = EI cos 90

P = 0.