Alternating Cur...

When $$100\space V$$ dc is applied across a coil, a current of $$1\space A$$ flows through it and when $$100\space V$$ ac of $$50\space Hz$$ is applied to the same coil, only $$0.5\space A$$ flows. The inductance of coil is

A charged capacitor discharges through a resistance R with time constant $$ \tau $$. The two are now placed in series across an AC source of angular frequency $$\displaystyle \omega = \frac {1} {\tau} $$ . The impedance of the circuit will be:

The resonant frequency of an L-C circuit is

A series LCR circuit is connected across a source of alternating emf of changing frequency and resonates at frequency $$\text{f}_o$$. Keeping capacitance constant, if the inductance (L) is increased by $$\sqrt{3}$$ times and resistance(R) is increased  by 1.4 times, the resonant frequency now is:

In a LR circuit of $$3\;mH$$ inductane and $$4\;\Omega$$ resistance, emf $$E=4\;cos\;(1000\;t)$$ volt is applied. The amplitude of current is:

In a purely inductive circuit, the current is

If the power factor in a circuit is unit, then the impedance of the circuit is

Inductive reactance of a coil is expressed in

An AC generator producing $$10V$$ (rms) at $$200rad/s$$ is connected in series with a $$50\Omega $$ resistor, a $$400mH$$ inductor and a $$200\mu F$$ capacitor. The rms voltage across the inductor is 

An inductor and a resistor are connected to an ac supply of $$50 V$$ and $$50 Hz$$. If the voltage across the resistor is $$40 V$$ the voltage across the inductor will be: