The RMS value of current in an AC circuit is \(10 ~\text A.\) The peak current in the circuit is:
1. \(1.41 ~\text A\)
2. \(14.1 ~\text A\)
3. \(7.07~\text A\)
4. \(0.707 ~\text A\)
In an AC circuit, alternating voltage \(e=200 \sqrt{2} \sin 100 t\) Volt is connected to a capacitor of capacity \(1~\mu \text{F}\). The RMS value of the current in the circuit is:
1. \(100\) mA
2. \(200\) mA
3. \(20\) mA
4. \(10\) mA
A pure inductor of \(25.0~\text{mH}\) is connected to an AC source of \(220~\text{V}.\) The RMS current in the circuit is:
(The frequency of the source is \(50~\text{Hz}\))
1. \(20~\text{A}\)
2. \(25~\text{A}\)
3. \(28~\text{A}\)
4. \(32~\text{A}\)
A lamp is connected in series with a capacitor. Predict your observations for DC and AC connections:
| 1. | When a DC source is connected to a capacitor, the lamp will not glow in a steady-state condition. |
| 2. | When an AC source is connected to a capacitor, the lamp will glow. |
| 3. | Both (1) and (2) are correct. |
| 4. | None of these. |
A sinusoidal voltage of peak value \(283~\text{V}\) (assuming that the frequency of the source can be varied) is applied to a series \(LCR\) circuit in which \(R=3~\Omega\), \(L=25.48~\text{mH},\) and \(C= 796~\mu\text{F}.\) The current in the circuit at the resonance is:
1. \(60~\text{A}\)
2. \(66.7~\text{A}\)
3. \(65~\text{A}\)
4. \(63.3~\text{A}\)
An inductance coil has a reactance of \(100~\Omega\). When an AC signal of frequency \(1000\) Hz is applied to the coil, the applied voltage leads the current by \(45^\circ\). The self-inductance of the coil is:
1. \( 1.1 \times 10^{-2} \mathrm{~H} \)
2. \(1.1 \times 10^{-1} \mathrm{~H} \)
3. \(5.5 \times 10^{-5} \mathrm{~H} \)
4. \(6.7 \times 10^{-7} \mathrm{~H} \)
In an ac circuit, the instantaneous e.m.f. and current are given by
\(\begin{aligned} & e=100 \sin 30 t \\ & i=20 \sin \left(30 t-\frac{\pi}{4}\right) \end{aligned}\)
In one cycle of ac, the average power consumed by the circuit and the wattless current are, respectively:
1. \(50, 10\)
2. \(\frac{1000}{\sqrt{2}},10\)
3. \(\frac{50}{\sqrt{2}},0\)
4. \(50,0\)
An alternating current is given by:
\(i=i_1\sin\omega t+i_2\cos \omega t. \)
What is the RMS value of the current?
| 1. | \( \dfrac{1}{\sqrt{2}}\left(i_1^2+i_2^2\right)^{1/2} \) | 2. | \(\dfrac{1}{\sqrt{2}}\left(i_1+i_2\right)^2 \) |
| 3. | \( \dfrac{1}{2}\left(i_1^2+i_2^2\right)^{1/2} \) | 4. | \( \dfrac{1}{\sqrt{2}}\left(i_1+i_2\right) \) |
The peak voltage in a 220 V AC source is
1. 220 V
2. about 160 V
3. about 310 V
4. 440 V
The power dissipated in an L-C-R series circuit connected to an AC source of emf E is: