Alternating Current

The potential differences across the resistance, capacitance and inductance are 80 V, 40 V and 100 V respectively in an L-C-R circuit. The power factor of this circuit is

A small signal voltage V(t) = V₀ sin ωt is applied across an ideal capacitor C:

An inductor 20 mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf V = 10 sin 340 t. The power loss in A.C. circuit is :

A 100 Ω resistance and a capacitor of 100 Ω reactance are connected in series across a 220 V source. When the capacitor is 50% charged, the peak value of the displacement current is

Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?

An inductor 20 mH, a capacitor 100 μF and a resistor 50 Ω are connected in series across a source of emf, V = 10 sin 314 t. The power loss in the circuit is

A circuit when connected to an AC source of 12 V gives a current of 0.2 A. The same circuit when connected to a DC source of 12 V, gives a current of 0.4 A. The circuit is

A series LCR circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is π/3. If instead C is removed from the circuit, the phase difference is again π/3 between current and voltage. The power factor of the circuit is

A 40 μF capacitor is connected to a 200 V, 50 Hz ac supply. The rms value of the current in the circuit is, nearly:

A series LCR circuit containing 5.0 H inductor, 80 μF capacitor and 40 Ω resistor is connected to 230 V variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be:

An inductor of inductance L, a capacitor of capacitance C and a resistor of resistance 'R' are connected in series to an ac source of potential difference 'V' volts as shown in figures. Potential difference across L, C and R is 40 V, 10 V and 40 V, respectively. The amplitude of current flowing through LCR series circuit is 10√2. The impedance of the circuit is :

A step down transformer connected to an ac mains supply of 220 V is made to operate at 11 V, 44 W lamp. Ignoring power losses in the transformer, what is the current in the primary circuit?

A series LCR circuit with inductance 10 H, capacitance 10 μF, resistance 50 Ω is connected to an ac source of voltage, V = 200 sin(100 t) volt. If the resonant frequency of the LCR circuit is v₀ and the frequency of the ac source is v, then:

The peak voltage of the ac source is equal to :

A 12 V, 60 W lamp is connected to secondary of step down transformer, whose primary is connected to ac mains of 220 V. Assuming the transformer to be ideal, what is the current in the primary winding?

The net impedance of circuit (as shown in figure) will be (series circuit with R = 10 Ω, an inductor and a capacitor driven by an AC source; from the figure values X_L = 5 Ω and X_C = 10 Ω).

In a series LCR circuit, the inductance L is 10 mH, capacitance C is 1 μF and resistance R is 100 Ω. The frequency at which resonance occurs is:

For very high frequencies, the effective impedance of the circuit (shown in the figure) will be

If Z₁ and Z₂ are the impedances of the given circuits (a) and (b) as shown in figures, then choose the correct option.

The maximum power is dissipated for an ac in a/an

An ac source is connected to a capacitor C. Due to decrease in its operating frequency:

An ac source is connected in the given circuit. The value of φ will be: V = 220 sin(100πt + φ) volt

In an ideal transformer, the turns ratio is N_p/N_s = 1/2. The ratio V_s : V_p is equal to (the symbols carry their usual meaning):

A 10 μF capacitor is connected to a 210 V, 50 Hz source as shown in figure. The peak current in the circuit is nearly (π = 3.14):

To an ac power supply of 220 V at 50 Hz, a resistor of 20 Ω, a capacitor of reactance 25 Ω and an inductor of reactance 45 Ω are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively -

The peak value of an alternating current is 5 A and frequency is 60 Hz. How long will the current, starting from zero, take to reach the peak value?

An ac voltage $V=220\sin(2\times10^{3}t)\,$V is applied to a series LCR circuit. The current amplitude in the circuit is: [$L=10\,$mH, $C=25\,\mu$F, $R=100\,\Omega$]

An ac circuit contains a resistance of 1 kΩ, a capacitor of 0.1 μF and an inductor of 1 mH connected in series. The resonance frequency of the circuit is approximately: