Alternating current practice · Mixed difficulty

The power factor of LCR circuit at resonance is

Assertion (A): An inductance and a resistance are connected in series with an AC circuit. In this circuit, the current and the potential difference across the resistance logs behind potential difference across the inductance by an angle $\frac{\pi}{2}.$
Reason (R): In L - R circuit, voltage leads the current by phase angle which depends on the value of inductance and resistance both.

A $60 \mu {F}$ capacitor is connected to a $110 {~V}, 60 {~Hz} {AC}$ supply. Determine the rms value of the current in the circuit.

Statement (A): Flux leakage in a transformer can be minimized by winding the primary and secondary coils one over the other.

Statement (B): Core of the transformer is made of soft iron.

A coil has a resistance $10\, \Omega$ and an inductance of 0.4 Henry. It is connected to an AC source of $6.5 \mathrm{~V}, \frac{30}{\pi} \mathrm{Hz}$. The average power consumed in the circuit, is :-

Given below are two statements:

Statement I: Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an AC source, when resonance occurs.

Statement II: Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage.

In the light of the above statements, choose the correct answer from the options given below:

In a series L-R growth circuit, if maximum current and maximum induced emf in an inductor of inductance $3 \mathrm{~mH}$ are $2 \mathrm{~A}$ and $6 \mathrm{~V}$ respectively, then the time constant of the circuit is

Can we use $15 \mathrm{~Hz}$ ac for lighting purposes?

AC voltage V(t) $= \mathrm{20 sin}\,\mathrm{\omega t}$ of frequency 50 Hz is applied to a parallel plate capacitor. The separation between the plates is 2 mm and the area is $1\,{m^2}.$ The amplitude of the oscillating displacement current for the applied AC voltage is ….
[Take, ${\varepsilon _0} = 8.85 \times {10^{ - 12}}F/m]$

An alternating voltage is represented as $E=20 \sin 300 t$. The average value of voltage over one cycle will be

In the non-resonant circuit, what will be the nature of the circuit for frequencies higher than the resonant frequency

A 10 ohm resistance, 5 mH coil and 10 μF capacitor are joined in series. When a suitable frequency alternating current source is joined to this combination, the circuit resonates. If the resistance is halved, the resonance frequency

A coil of resistance $R$ and inductance $L$ is connected across an $a.c.$ power supply of $r.m.s.$ voltage ${V}$. The power dissipated in the coil is

An LCR series circuit is compared with a damped oscillator of mass ' ${m}$ ' with force constant ${K}$ and damping coefficient ' ${b}$ '. The correct matching of quantities in damped oscillator analogous with those in LCR circuit is

In a series $L - C - R$ resonance circuit, if we change the resistance only, from a lower to higher value,

An alternating current source of frequency 100 Hz is joined to a combination of a resistance, a capacitance and a coil in series. The potential difference across the coil, the resistance and the capacitor is 46, 8 and 40 volt respectively. The electromotive force of alternating current source in volt is

In a series $L C R$ circuit, at resonance, the bandwidth frequency can be represented as

A voltage of peak value 283 V and varying frequency is applied to a series L – C – R combination in which $R = 3\;\mathrm{\Omega }$ , $L = 25$ mH and $C = 400\mu \mathrm{F}$ . The frequency (in Hz)of the source at which maximum power is dissipated in the above, is

In a step-up transformer the turn’s ratio is 10. If the frequency of the current in the primary coil is 50Hz then the frequency of the current in the secondary coil will be……… Hz

In $R-L$ series $D C$ circuit $E=20 \mathrm{~V}, L=5 \mathrm{mH}$ and $R=1 \Omega$. If battery is connected at $t=0$ sec. then find time when $\mathbf{I}$ is $12.6 \mathrm{~A}$.

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

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

A resistance $R$, an inductance $L=0.01 {H}$ and a capacitance $C$ are connected in series. When a voltage $V=400 \cos \left(300 t-10^{\circ}\right) {V}$ is applied to the series combination, the current flowing is $10 \sqrt{2} \cos \left(3000 t-55^{\circ}\right)$ A. Find the capacitance of capacitor in microfarads.

When $100 \mathrm{~V} \mathrm{DC}$ is applied across a solenoid, a current of $1 \mathrm{~A}$ flows in it. When $100 \mathrm{V} \mathrm{~AC}$ is applied across the same coil, the current drops to $0.5 \mathrm{~A}$. If the frequency of the $\mathrm{AC}$ source is $50 \mathrm{~Hz}$, the impedance and inductance of the inductor for the given $\mathrm{AC}$ circuit are

An R-L-C series circuit with $100\,\Omega$ resistance is connected to an AC source of $200 {~V}$ and $\omega=300 \,{rad} / {s}$. When only capacitor is removed, the current lags behind voltage by $60^{\circ}$. When only inductor is removed, the current leads voltage by $60^{\circ}$. The power dissipated in the R-L-C circuit is

At high frequency, the capacitor offer

Statement (A): An ac emf which oscillates symmetrically about zero, the current it sustains also oscillates symmetrically about zero.

Statement (B): In any circuit element, current is always in the phase with voltage.

A resistance of $300\, \Omega$ and an inductance of $\frac{1}{\pi}$ henry are connected in series to a ac voltage of 20 volts and $200 {~Hz}$ frequency. The phase angle between the voltage and current is

Write the equation of a sinusoidal voltage of rms valus $220 \mathrm{~V}$ and frequency $50 \mathrm{~Hz}$

Assertion: If the frequency of alternating current in an ac circuit consisting of an inductance coil is increased then current gets decreased.

Reason: The current is inversely proportional to frequency of alternating current.