Alternating Current Questions

To an ac power supply of $220\text{V}$ at $50\text{Hz}$, a resistor of $20\Omega$, a capacitor of reactance $25\Omega$ and an inductor of reactance $45\Omega$ are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively:

In an ac circuit an alternating voltage $e=200\sqrt{2}\sin 100t$ volts is connected to capacitor of capacity $1\mu \text{F}$. The r.m.s. value of the current in the circuit is:

An ac voltage is applied to a resistance $R$ and inductor $L$ in series. If $R$ and the inductive reactance are both equal to $3\Omega$, the phase difference between the applied voltage and the current in the circuit is:

The voltage gain of the following amplifier is:

A $50\text{Hz}$ a.c. source of $20\text{volts}$ is connected across $R$ and $C$ as shown in figure. The voltage across $R$ is $12\text{volt}$. The voltage across $C$ is:

The circuit shown below acts as:

In an a.c. circuit the e.m.f. ($e$) and the current ($i$) at any instant are given respectively by $e=E_0\sin \omega t$ and $i=I_0\sin (\omega t-\pi /2)$. The average power in the circuit over one cycle of a.c. is:

Power dissipated in an LCR series circuit connected to an a.c source of emf $ϵ$ is:

For the potential $V$ shown in the figure (triangular wave), the $r.m.s.$ value is:

A coil has $R=30\Omega$ and $X_L=20\Omega$ at $50\text{Hz}$. If connected to $200\text{V},100\text{Hz}$ source, the current is:

$i=\sin (100\pi t)$ and $e=\sin (100\pi t+\pi /3)$. Average power in Watts is:

In an electrical circuit $R,L,C$ and an a.c voltage source are all connected in series. When $L$ is removed, the phase difference is $\pi /3$. If instead $C$ is removed, the phase difference is again $\pi /3$. The power factor of the circuit is:

A series R-C circuit is connected to an alternating voltage source. Consider two situations:(i) When capacitor is air filled.(ii) When capacitor is mica filled.Current through resistor is $i$ and voltage across capacitor is $V$ then:

Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?

The potential differences across the resistance, capacitance and inductance are $80\text{V},40\text{V}$ and $100\text{V}$ respectively in an L-C-R circuit. The power factor of this circuit is: