Alternating Cur...

The ac generator in the Figure supplies 150 $$\displaystyle V_{(max)}$$ at 50 Hz. With the switch open as shown in the diagram, the resulting current leads the generator emf by $$60^{\circ}$$. With the switch in position 1, the current lags the generator emf by $$30^{\circ}$$. When the switch is in position 2, the maximum current is 3A. Then, the value of R is:

An ideal choke takes a current of $$10\ Amperes$$ when connected to an ac supply of  $$125\ volt$$ and $$50\ Hz$$. A pure resistor under the same condition takes a current of  $$12.5\ Ampere$$. If the two are connected to an ac supply of $$100\sqrt {2}$$ volt and $$40\ Hz,$$  then the current in a series combination of the above resistor and inductor is:

For the circuit shown in the Figure, the current through the inductor is 0.9 A while the current through the condenser is 0.4 A

A circuit containing a $$80\ mH$$ inductor and $$60 \ \mu F$$ capacitor in series is connected to a $$230\ V, 50\ Hz$$ supply. If the resistance in the circuit is negligible then the current amplitude will be

A high-impedance ac voltmeter is connected in turn across the inductor, the capacitor, and the resistance in a series circuit having an ac source of 100 V(rms) and gives the same reading in volts in each case. Then, this reading is:

In which of the following circuit, there may be no change in current with increase in the frequency when same ac current is passed through them:

In an $$L-C-R$$ circuit the capacitance is changed from $$C$$ to $$4C$$. For the same resonant frequency, the inductance should be changed from $$L$$ to

A coil of negligible resistance is connected in series with a 90 $$\Omega$$ resistor across a 120 V, 60 Hz line. An ac voltmeter reads 90 V across the resistance, then the inductance of the coil is approximately

With increase in frequency of an ac supply, the impedance of an $$L-C-R$$ series circuit

The turning circuit of a radio receiver has a resistance of $$50\ \Omega$$, an inductor of $$10\ \text{mH}$$ and a variable capacitor. A $$1\ \text{MHz}$$ radio wave produces a potential difference of $$0.1\ \text{mV}$$. The values of the capacitor to produce resonance is (Take $${\pi}^{2}=10$$):