Alternative Current MCQ Level - 1 - Class 12 MCQ

The natural frequency (ω₀) of oscillations in L-C circuit is given by

In L-C-R series circuit the resonance condition in terms of capacitive reactance (X_C) and inductive reactance (X_L) is

Average power generated in an inductor connected to an AC source is

In L-C-R circuit if resistance increases, quality factor

An electric bulb has a rated power of 50 W at 100 V. If it is used on an AC source 200 V, 50 Hz, a choke has to be used in series with it. The should have an inductance of

From figure shown below a series L-C-R circuit connected to a variable frequency 200 V source. C = 80μF and R = 40W . Then the source frequency which drive the circuit at resonance is 

In an L-C-R series AC circuit, the voltage across each of components. L,C and R is 50 V. The voltage across the L-C combination will be

In an L-C-R circuit, capacitance is changed from C to 2C. For the resonant frequency to remain unchanged, the inductance should be changed from L to

Which of the following statement is incorrect?

The impedance of a circuit, when a resistance R and an Inductor of inductance L are connected in series in an AC circuit of frequency f, is

ln a series L-C-R circuit, resistance R = 10W and the impedance Z = 10W. The phase difference between the current and the voltage is.

A circuit consists of an inductance of 0.5 mH and a capacitor of 20μF. The frequency of the L-C oscillations is approximately

An inductor is connected to an AC source. When compared to voltage, the current in the lead wires 

An inductance 1 H is connected in series with an AC source of 220 V and 50 Hz. The inductive reactance (in ohm) is

The power factor of an AC circuit having resistance R and inductance L (connected in series) and an angular velocity ω is

If the capacity of a condenser is 1 F, then its resistance in a DC circuit will be

A capacitor 50μF is connected to a supply of 220 V and angular frequency 50 rad s^-1. The value of rms current in the circuit is

In a series L-C-R circuit the frequency of a 10 V AC voltage source is adjusted in such a fashion that the reactance of the inductor measures15  and that of the capacitor11. If R = 3, the potential difference across the series combination of L and C will be

A circuit draws 330 W from a 110 V, 60 Hz AC line. The power factor is 0.6 and the current lags the voltage. The capacitance of a series capacitor that will result in a power factor of unity is equal to

In L-R circuit, resistance is 8  and inductive reactanceis 6,  then impedance is

In L-C-R circuit, an alternating emf of angular frequency ω is applied then the total impedance will be

In AC circuit a resistance of R is connected in series with an inductance L. If the phase difference between the current and voltage is 45°, the inductive reactance will be

The current which does not contribute to the power consumed in an AC circuit is called?

The power loss in AC circuit will be minimum when

In a series combination R = 300, L = 0.9 H, C = 2.0 μF, ω = 1000 rads^-1, the impedance of the circuit is

For a series L-C-R circuit, the phase difference between current and voltage at the condition of resonance will be

In a L-R circuit of 3 mH inductance and 4 resistance, emf E = 4 cos 1000tV is applied. The amplitude of emf is