In the shown AC source, the voltage is given as V = 20 cos 2000t. Neglecting source resistance, the voltmeter and ammeter readings will be:
0 V, 1.4 A
We analyze the given circuit using impedance calculations.
- Given AC source: V = 20 cos(2000t).
- Inductive reactance: XL = ωL = (2000) × (5 × 10-3) = 10 Ω.
- Capacitive reactance: XC = 1 / (ωC) = 1 / (2000 × 50 × 10-6) = 10 Ω.
- Net reactance: Xnet = XL - XC = 10 - 10 = 0 Ω.
- Total resistance in series: R = 6Ω + 4Ω = 10Ω.
- Total impedance: Z = √(R² + Xnet²) = √(10² + 0²) = 10 Ω.
- Current: I = V / Z = 20 / 10 = 2 A (RMS value = 1.4 A).
- Voltage across inductor and capacitor (voltmeter reading) = 0 V due to resonance.
Thus, the correct answer is (a).
Important Questions from Alternating Current
Match List - I with List - II.
List - I List - II (A) The current lags behind the emf by 4π in phase (I) A.C. circuit containing only an inductor (B) The e.m.f. lags behind the current by 4π in phase (II) A.C. circuit with resistance and inductance in series (C) The current lags behind the e.m.f. in phase by 2π (III) A.C. circuit containing only a capacitor (D) The e.m.f. lags behind the current in phase by 2π (IV) A.C. circuit with resistance and capacitor in series Choose the correct answer from the options given below:
A e.m.f. es=50sin314t is applied across a pure capacitor of 637μF. The instantaneous current I is:
Match List - I with List - II.
List - I List - II (A) Resistive Circuit (I) No power dissipation (B) Purely inductive or capacitive circuit (II) Maximum power dissipation because XL=XC (C) LCR series circuit (III) Power dissipated only in resistor (D) Power dissipated at resonance in LCR circuit (IV) Maximum power dissipation Choose the correct answer from the options given below:
The same current is flowing in two AC circuits. The first circuit contains a pure inductor and the second, a capacitor. If the frequency of the AC is increased, then the current will:
A 25 μF capacitor, a 0.10 H inductor, and a 25 Ω resistor is connected in series with an AC source of emf ε = 310 sin 314t. What is the frequency of the AC source?
