Question

In a given circuit, the instantaneous values of alternating voltage and current are $V = 5 \sin(80\pi t + \pi)$ volts and $I = 5 \sin(80\pi t)$ amperes respectively. Find the average power consumed in the circuit.

• A. $0.0625\text{ W}$
• B. $1.25\text{ W}$
• C. $0.625\text{ W}$
• D. $-0.125\text{ W}$

Hint:

When two electrical wave parameters are completely out of phase by $\pi$ radians ($180^\circ$), the power factor $\cos\phi$ drops to $-1$. This means the system power expression simply becomes $-\frac{V_0 I_0}{2} = -\frac{0.25}{2} = -0.125\text{ W}$.

Answer 1

The Correct Option is D