Alternating Current

An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V (rms), 50 Hz AC supply, the series inductor needed for it to work is close to :

A sinusoidal voltage of peak value 283 V and angular frequency 320/s is applied to a series LCR circuit. Given that R=5 $\Omega$, L=25 mH and C=1000 $\mu$F. The total impedance, and phase difference between the voltage across the source and the current will respectively be :

In an a.c. circuit, the instantaneous e.m.f. and current are given by e = 100 sin 30 t i = 20 sin $\left( {30t - {\pi \over 4}} \right)$ In one cycle of a.c., the average power consumed by the circuit and the wattless current are, respectively

An ideal capacitor of capacitance $0.2\,\mu F$ is charged to a potential difference of $10$ $V.$ The charging battery is then disconnected. The capacitor is then connected to an ideal inductor of self inductance $0.5$ $mH.$ The current at a time when the potential difference across the capacitor is $5$ $V,$ is :

A circuit connected to an ac source of emf e = e₀sin(100t) with t in seconds, gives a phase difference of $\pi$/4 between the emf e and current i. Which of the following circuits will exhibit this ?

An alternating voltage v(t) = 220 sin 100 $\pi$t volt is applied to a purely resistance load of 50$\Omega$ . The time taken for the current to rise from half of the peak value to the peak value is :

A series AC circuit containing an inductor (20 mH), a capacitor (120 $\mu$F) and a resistor (60 $\Omega$) is driven by an AC source of 24V/50 Hz. The energy dissipated in the circuit in 60 s is :

A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the correct equivalence would be:

In LC circuit the inductance L = 40 mH and capacitance C = 100 $\mu$F. If a voltage V(t) = 10sin(314t) is applied to the circuit, the current in the circuit is given as :

A 750 Hz, 20 V (rms) source is connected to a resistance of 100 $\Omega$, an inductance of 0.1803 H and a capacitance of 10 $\mu$F all in series. The time in which the resistance (heat capacity 2 J/^oC) will get heated by 10^oC. (assume no loss of heat to the surroudnings) is close to :