Figure shows a series LCR circuit connected to a variable frequency 230 V source. L = 5.0 H, C = 80 $\mathrm{\mu }$F, R = 40$\Omega$ 

The amplitude of current at the resonating frequency is:

Figure shows a series LCR circuit connected to a variable frequency 230 V source. L = 5.0 H, C = 80uF, R = 40 $\Omega$

The RMS potential drop across the resistor under the resonating condition is:

A radio can tune over the frequency range of a portion of the MW broadcast band: (800 kHz to 1200 kHz). If its LC circuit has an effective inductance of 200 µH, what must be the range of its variable capacitor?

$$\begin{gathered} \left(1\right) 87.8 pF-197.7 pF \\ \left(2\right) 88.3 pF-198.8 pF \\ \left(3\right) 89.3 pF-199.1 pF \\ \left(4\right) 89.1 pF-196.9 pF \end{gathered}$$

A series LCR circuit with R = 20 Ω, L = 1.5 H and C = 35 µF is connected to a variable-frequency 200 V ac supply. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one complete cycle?

$$\begin{gathered} \left(1\right) 2200 W \\ \left(2\right) 2000 W \\ \left(3\right) 2020 W \\ \left(4\right) 2120 W \end{gathered}$$

A 60 µF capacitor is connected to a 110 V, 60 Hz ac supply. The RMS value of the current in the circuit is:

$$\begin{gathered} \left(1\right) 2.49 A \\ \left(2\right) 2.12 A \\ \left(3\right) 1.97 A \\ \left(4\right) 1.24 A \end{gathered}$$

An LC circuit contains a 20 mH inductor and a 50 µF capacitor with an initial charge of 10 mC. The resistance of the circuit is negligible. Let the instant the circuit is closed be t = 0. What is the total energy stored initially? 

A coil of inductance 0.50 H and resistance 100 $\Omega$ is connected to a 240 V, 50 Hz ac supply. What is the maximum current in the coil?

In a series LCR circuit, voltage leads the current when:
(Given that ${\mathrm{\omega }}_0=$resonant angular frequency)

A coil of inductance 0.50 H and resistance 100 Ω is connected to a 240 V, 50 Hz ac supply. What is the time lag between the voltage maximum and the current maximum?

$$\begin{gathered} \left(1\right) 4.11\times {10}^{-3} s \\ \left(2\right) 2.10\times {10}^{-3} s \\ \left(3\right) 3.19\times {10}^{-3} s \\ \left(4\right) 2.23\times {10}^{-3} s \end{gathered}$$

A 100 µF capacitor in series with a 40 $\Omega$ resistance is connected to a 110 V, 60 Hz supply. What is the maximum current in the circuit?

 A circuit containing an 80 mH inductor and a 60 µF capacitor in series is connected to a 230 V, 50 Hz supply. The resistance of the circuit is negligible. the current amplitude is:

A circuit containing an 80 mH inductor and a 60 µF capacitor in series is connected to a 230 V, 50 Hz supply. The resistance of the circuit is negligible. What is the average power transferred to the inductor?

A series LCR circuit with L = 0.12 H, C = 480 nF, R = 23 $\Omega$ is connected to a 230 V variable frequency supply. What is the source frequency for which current amplitude is maximum? 

A series LCR circuit with L = 0.12 H, C = 480 nF, R = 23 $\Omega$ is connected to a 230 V variable frequency supply. What is the Q-factor of the given circuit?

 A small town with a demand of 800 kW of electric power at 220 V is situated 15 km away from an electric plant generating power at 440 V. The resistance of the two wirelines carrying power is 0.5 $\Omega$ per km. The town gets power from the line through a 4000-220 V step-down transformer at a sub-station in the town. The line power loss in the form of heat is:

$$\begin{gathered} \left(1\right) 100 kW \\ \left(2\right) 500 kW \\ \left(3\right) 400 kW \\ \left(4\right) 600 kW \end{gathered}$$

At a hydroelectric power plant, the water pressure head is at a height of 300 m and the water flow available is $100 m^3 s^{-1}$. If the turbine generator efficiency is 60%, the electric power available from the plant is: $\left(g=9.8 m s^{-2}\right).$

A power transmission line feeds input power at 2300 V to a step-down transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?

What is the Q-factor of a series LCR circuit with L = 3.0 H, C = 27µF, and R = 7.4 Ω?

A simple electric motor has an armature resistance of $1\mathrm{\Omega }$ and runs from a d.c. source of 12 V. It draws a current of 2 A when unloaded. When a certain load is connected to it, its speed reduces by 10% of its initial value. The current drawn by the loaded motor is

The time required for a 50 Hz sinusoidal alternating current to change its value from zero to the r.m.s. value

When 100 volt d.c. is applied across a solenoid, a current of 1.0 A flows in it. When 100 volt a.c. is appliead across the same coil, the current drops to 0.5 A. If the frequency of a.c. source is 50 Hz the impedance and inductance of the solenoid is

In a series RLC circuit, potential differences across R, L and C are 30 V, 60 V and 100 V respectively as shown in figure. The e.m.f. of source (in volts) is

In series LCR circuit, the phase difference between voltage across L and voltage across C is

The reactance of a circuit is zero. It is possible that the circuit contains:

In the given figure, a lamp P is in series with an iron-core inductor L. When the switch S is closed, the brightness of the lamp rises relatively slowly to its full brightness than it would do without inductor in circuit. This is due to:

In a series R-L-C circuit, the frequency of the source is half of the resonance frequency. The name of the circuit will be:

If the RMS current in a 50 Hz AC circuit is 5 A, the value of the current 1/300 s after its value becomes zero is:

An alternating current generator has an internal resistance ${\mathrm{R}}_{\mathrm{g}}$ and an internal reactance ${\mathrm{X}}_{\mathrm{g}}$. It is used to supply power to a passive load consisting of a resistance ${\mathrm{R}}_{\mathrm{g}}$ and a reactance ${\mathrm{X}}_{\mathrm{L}}$. For maximum power to be delivered from the generator to the load, the value of ${\mathrm{X}}_{\mathrm{L}}$ is equal to :

When a voltage measuring device is connected to AC mains, the meter shows the steady input voltage of 220 V. This means:

To reduce the resonant frequency in an L-C-R series circuit with a generator: