List of top Physics Questions on Alternating current asked in KEAM

A series LCR circuit consists of a variable capacitor connected to an inductor of inductance 50 mH,resistor of resistance 100 Ω and an AC source of angular frequency 500 rad/s. The value of capacitance so that maximum current may be drawn into the circuit is:

When an A.C. voltage of V = 330 sin(100πt) is applied to a capacitor, it produces a current of 1 = 1.5 cos(100πt). The capacitive reactance of the capacitor is

The INCORRECT statement is

The $Q$ factor for a damped oscillator is given by the

Two bulbs 60 W and 100 W designed for voltage 220 V are connected in series across 220 V source. The net power dissipated is

An $LCR$ series $AC$ circuit is at resonance with $10\, V$ each across $L, C$ and $R$. If the resistance is halved, the respective voltages across $L, C$ and $R$ are

A lamp consumes only $25\%$ of the peak power in an ac circuit. The phase difference between the applied voltage and the current is

A voltage $V_{PQ} = V_0 \, \cos \, \omega t$ (where $V_0$ is a real amplitude) is applied between the points P and Q in the network shown in the figure. The values of capacitance and inductance are $C = \frac{1}{\omega R \sqrt{3}}$ and $L = \frac{R \sqrt{3}}{\omega}$ Then, the total impedance between P and Q is

An $LCR$ series circuit is at resonance. Then

In a pure inductive AC circuit

The power dissipated in an AC circuit is zero if the circuit is

In an L-C-R series AC circuit, if $\omega_0$ is the resonant angular frequency, then the quality factor (Q-factor) is given by

A transformer has an efficiency of 80%. It is connected to a power input of $ 5 \,kW $ at $ 200\, V $ . If the secondary voltage is $ 250\, V $ , the primary and secondary currents are respectively