Alternating Cur...

An inductor coil stores U energy when I current is passed through it and dissipates energy at the rate of P. The time constant of the circuit, when this coil is connected across a battery of zero internal resistance is

The time constant of a circle is $$10 sec$$. When $$10$$ $$\Omega$$ resistance is connected in a series, then constant of a circuit is now $$2$$ sec. Self-inductance of circuit will be

A series R LC circuit has a bandwidth of $$300 rad/sec$$ at a resonance frequency of $$3000 rad/ sec $$ when excited by voltage  source of $$100 V$$. The inductance of coil is $$0.1 H$$ the value of R and voltage across C are respectively.

Impedence of L-R circuit is

In an $$A.C$$. circuit, a resistance $$R=40\ \Omega$$ and an inductance $$L$$ are connected in series. If the phase angle between voltage and current is $$45^{o}$$, then the value of the  inductive reactance will be

In the following circuit the emf source is $$E_0 = 200 \ volt, \ R = 20 \Omega$$, L = 0.1 henry. C = 10.6 farad and frequency is variable then the current at frequency f = 0 and f = $$\infty$$ is

In the given circuit,$$\mathrm { V } _ { \mathrm { CE } }$$ =30 V, $$\mathrm { V } _ { \mathrm { BB } }$$ =20 V, $$R _ { B }$$ 1 M $$\Omega$$ ,$$R _ { C }$$ 10 K $$\Omega$$ Neglecting $$v _ { \mathrm { BE } }$$  and taking $$\beta$$ 50, the values of $$\mathbf { I } _ { C }$$  and $$\mathbf { I } _ { \mathrm { E } }$$ are respectively 

An inductor ($$X_L=2 \Omega$$) a capacitor ($$X_c=8 \Omega$$) and a resistance $$(8 \Omega)$$ are connected in series with an ac source. The voltage output of A.C source is given by v=10 cos 100 $$\pi t$$. The instantaneous p.s. between A and B, when it is half of the voltage output from source at that instant will be:

A coil has reactance of $$100\Omega$$ when the frequency is $$50 Hz$$. If the frequency becomes $$150 Hz$$, then the reactance will be

If the power factor changes from $$\dfrac {1}{2}$$ to $$\dfrac {1}{4}$$ then the increase in impedance in AC circuit with constant resistance is