To determine the power loss in the given RLC circuit with an inductor \(L = 20 \, \text{mH}\), a capacitor \(C = 100 \, \mu \text{F}\), and a resistor \(R = 50 \, \Omega\), connected to a source of emf \(V = 10 \sin 314 t\), let's proceed step-by-step:
The given voltage source is in the form \( V = 10 \sin 314 t \). Comparing it with the standard form \( V = V_0 \sin \omega t \), we identify \(\omega = 314 \, \text{rad/s}\).
The total impedance \(Z\) of a series RLC circuit is given by:
Z = \sqrt{R^2 + (X_L - X_C)^2}
Substitute the values:
Z = \sqrt{50^2 + (6.28 - 31.85)^2} \, \Omega = \sqrt{50^2 + (-25.57)^2} \, \Omega = \sqrt{2500 + 653.62} \, \Omega = \sqrt{3153.62} \, \Omega \approx 56.15 \, \Omega
The maximum current \(I\) is obtained from the maximum voltage \(V_0 = 10 \, \text{V}\):
I = \frac{V_0}{Z} = \frac{10}{56.15} \approx 0.178 \, \text{A}
The average power dissipated in the resistor is given by:
P = I^2 R = (0.178)^2 \times 50 \approx 0.79 \, \text{W}
Thus, the power loss in the circuit is 0.79 W, which matches option 2. Hence, the correct answer is 0.79 W.