Alternating Current

A series LCR circuit with R=20 , L=1.6 H and C=40 F is connected to a variable frequency a.c. source. The inductive reactance at resonant frequency is .

An inductor of 10 mH, capacitor of 0.1 μF and a resistor of 100 Ω are connected in series across an a.c. power supply 220 V, 70 Hz. The power factor of the given circuit is 0.5. The difference in the inductive reactance and capacitive reactance is 3 Ω. The value of is .

An inductor stores 16 J of magnetic field energy and dissipates 32 W of thermal energy due to its resistance when an a.c. current of 2 A (rms) and frequency 50 Hz flows through it. The ratio of inductive reactance to its resistance is . ( = 3.14)

Using a variable frequency a.c. voltage source the maximum current measured in the given LCR circuit is 50 mA for V = 5 (100t). The values of L and R are shown in the figure. The capacitance of the capacitor (C) used is . [figure]

For ac circuit shown in figure, R = 100 k and C = 100 pF and the phase difference between Vin and (VB - VA) is 90 . The input signal frequency is 10x rad/sec, where 'x' is . [figure]

An inductor of reactance 100 , a capacitor of reactance 50 , and a resistor of resistance 50 are connected in series with an AC source of 10 V, 50 Hz. Average power dissipated by the circuit is W.

An inductor of self inductance 1 H is connected in series with a resistor of 100 ohm and an ac supply of 100 volt, 50 Hz. Maximum current flowing in the circuit is A.

In a series LCR circuit, a resistor of 300 , a capacitor of 25 nF and an inductor of 100 mH are used. For maximum current in the circuit, the angular frequency of the ac source is 104 radians s-1

When a coil is connected across a 20 V dc supply, it draws a current of 5 A. When it is connected across 20 V, 50 Hz ac supply, it draws a current of 4 A. The self inductance of the coil is mH. (Take = 3)

A capacitor of reactance 4 3 and a resistor of resistance 4 are connected in series with an ac source of peak value 8 2 V. The power dissipation in the circuit is W.

An alternating emf E = 110 2 100t volt is applied to a capacitor of 2 , the rms value of current in the circuit is mA.

When a dc voltage of 100 V is applied to an inductor, a dc current of 5 A flows through it. When an ac voltage of 200 V peak value is connected to inductor, its inductive reactance is found to be 20 3 . The power dissipated in the circuit is W.

For a given series LCR circuit it is found that maximum current is drawn when value of variable capacitance is 2.5 nF. If resistance of 200 and 100 mH inductor is being used in the given circuit. The frequency of ac source is 103 Hz (given 2 = 10)

An ac source is connected in given series LCR circuit. The rms potential difference across the capacitor of 20 is V. [figure]

An alternating current at any instant is given by i= [6+ 56 (100 t+ /3) ] A. The rms value of the current is A.

A power transmission line feeds input power at 2.3 kV to a step down transformer with its primary winding having 3000 turns. The output power is delivered at 230 V by the transformer. The current in the primary of the transformer is 5 A and its efficiency is 90\%. The winding of transformer is made of copper. The output current of transformer is A.

A series LCR circuit with L= 100 mH, C= 10-3 F and R=10 , is connected across an ac source of 220 V, 50 Hz supply. The power factor of the circuit would be .