Q 12-07-002NEETNEET 2025Top questionEasy
To an ac power supply of $220$ V at $50$ Hz, a resistor of $20\ \Omega$, a capacitor of reactance $25\ \Omega$ and an inductor of reactance $45\ \Omega$ are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively -
Answer: (B) $7.8$ A and $45°$
$$Z = \sqrt{R^2 + (X_L - X_C)^2} = \sqrt{20^2 + (45 - 25)^2} = 20\sqrt{2} \approx 28.3\ \Omega$$
$$I = \frac{220}{28.3} \approx 7.8\ \text{A}$$
$$\tan\phi = \frac{X_L - X_C}{R} = \frac{20}{20} = 1 \;\Rightarrow\; \phi = 45°$$
Solution by Sreeraj P, M.Sc Physics