Q. No.The reactance of a circuit is zero. It is possible that the circuit contains:
1. an inductor and a capacitor
2. an inductor but no capacitor
3. a capacitor but no inductor
4. All of the above
In the given figure, a lamp P is in series with an iron-core inductor L. When the switch S is closed, the brightness of the lamp rises relatively slowly to its full brightness than it would do without inductor in circuit. This is due to:
1. the low resistance of P
2. the induced emf in L
3. the low resistance of L
4. the low voltage of the battery B
In a series R-L-C circuit, the frequency of the source is half of the resonance frequency. The name of the circuit will be:
1. capacitive
2. inductive
3. purely resistive
4. data insufficient
If the RMS current in a \(50~\text{Hz}\) AC circuit is \(5~\text{A}\), the value of the current \(\dfrac{1}{300}~\text{s}\) after its value becomes zero is:
| 1. | \(5\sqrt2~\text{A}\) | 2. | \(5\sqrt{\dfrac32}~\text{A}\) |
| 3. | \(\sqrt{\dfrac56}~\text{A}\) | 4. | \(\dfrac{5}{\sqrt2}~\text{A}\) |
An alternating current generator has an internal resistance \(R_{g}\) and an internal reactance \(X_{g}\). It is used to supply power to a passive load consisting of a resistance \(R_{g}\) and a reactance \(X_{L}\). For maximum power to be delivered from the generator to the load, the value of \(X_{L}\) is equal to:
1. zero
2. \(X_g\)
3. \(-X_g\)
4. \(R_g\)
| 1. | input voltage cannot be AC voltage, but a DC voltage |
| 2. | maximum input voltage is \(220~\text{V}\) |
| 3. | the meter reads not \(v\) but \(<v^2>\) and is calibrated to read \(\sqrt{<v^2>}\) |
| 4. | the pointer of the meter is stuck by some mechanical defect |
To reduce the resonant frequency in an LCR series circuit with a generator:
| 1. | the generator frequency should be reduced |
| 2. | another capacitor should be added in parallel to the first |
| 3. | the iron core of the inductor should be removed |
| 4. | the dielectric in the capacitor should be removed |
An inductor of reactance \(1~\Omega\) and a resistor of \(2~\Omega\) are connected in series to the terminals of a \(6~\text{V}\) (RMS) AC source. The power dissipated in the circuit is:
1. \(8~\text{W}\)
2. \(12~\text{W}\)
3. \(14.4~\text{W}\)
4. \(18~\text{W}\)
The output of a step-down transformer is measured to be \(24\) V when connected to a \(12\) W light bulb. The value of the peak current is:
| 1. | \(\dfrac{1}{\sqrt{2}}~\text{A}\) | 2. | \(\sqrt{2}~\text{A}\) |
| 3. | \(2~\text{A}\) | 4. | \(2\sqrt{2}~\text{A}\) |
| (a) | Inductor and capacitor |
| (b) | Resistor and inductor |
| (c) | Resistor and capacitor |
| (d) | Resistor, inductor, and capacitor |
1. (b), (c)
2. (c), (d)
3. (b), (d)
4. (a), (d)
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