Q. No.In the transformer shown in the figure, the ratio of the number of turns of the primary to the secondary is N1/N2=1/50. If a voltage source of 10 V is connected across the primary, then the induced current through the load of 10 kΩ in the secondary is:
1. \(\frac{1}{20}~A\)
2. zero
3. \(\frac{1}{10}~A\)
4. \(\frac{1}{5}~A\)
In the circuit shown, the value of RMS current is 11 A. The potential difference across the inductor is:
1. 220 V
2. zero
3. 300 V
4. 200 V
In a heating arrangement, an alternating current having a peak value of \(28~\mathrm{A}\) is used. To produce the same heat energy, if direct current is used to produce the same amount of heat, then its magnitude will be:
| 1. | about \(14~\mathrm{A}\) | 2. | about \(28~\mathrm{A}\) |
| 3. | about \(20~\mathrm{A}\) | 4. | cannot say |
In the circuit shown, the AC source has a voltage
V = 20 cos(ωt) volts with ω= 2000 rad/s. The amplitude of the current will be nearest to:
1. 2 A
2. 3.3 A
3. 2/ A
4. A
The AC source in the circuit shown in the figure produces a voltage \(V = 20\cos(2000t)\) volts. Neglecting source resistance, the voltmeter and ammeter readings will be (approximately):
1. \(4~\text{V}, 2.0~\text{A}\)
2. \(0~\text{V}, 2~\text{A}\)
3. \(5.6~\text{V}, 1.4~\text{A}\)
4. \(8~\text{V}, 2.0~\text{A}\)
An AC ammeter is used to measure the current in a circuit. When a given direct current passes through the circuit, the ac ammeter reads 6 A. When another alternating current passes through the circuit, the AC ammeter reads 8 A. Then the reading of this ammeter if DC and AC flow through the circuit simultaneously is:
1. A
2. 14 A
3. 10 A
4. 15 A
If q is the capacitor's charge and i is the current at time t, the voltage V will be:
| 1. | \(\mathrm{L} \frac{\mathrm{di}}{\mathrm{dt}}+\mathrm{iR}-\frac{\mathrm{q}}{\mathrm{C}}=\mathrm{V}\) |
| 2. | \(\mathrm{L} \frac{\mathrm{di}}{\mathrm{dt}}-\mathrm{iR}+\frac{\mathrm{q}}{\mathrm{C}}=\mathrm{V}\) |
| 3. | \(\mathrm{L} \frac{\mathrm{di}}{\mathrm{dt}}+\mathrm{iR}+\frac{\mathrm{q}}{\mathrm{C}}=\mathrm{V}\) |
| 4. | \(\mathrm{L} \frac{\mathrm{di}}{\mathrm{dt}}-\mathrm{iR}-\frac{\mathrm{q}}{\mathrm{C}}=\mathrm{V}\) |
A capacitor and a resistor are connected in series across the a.c supply. Which of the following phasor diagrams may be correct?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
A direct current of \(5~ A\) is superimposed on an alternating current \(I=10sin ~\omega t\) flowing through a wire. The effective value of the resulting current will be:
| 1. | \(15/2~A\) | 2. | \(5 \sqrt{3}~A\) |
| 3. | \(5 \sqrt{5}~A\) | 4. | \(15~A\) |
An L-C-R series circuit with 100 Ω resistance is connected to an AC source of 200 V and an angular frequency of 300 rad/s. When only the capacitance is removed, the current lags behind the voltage by . When only the inductance is removed, the current leads the voltage by . Calculate the power dissipated in the L-C-R circuit.
1. 200 W
2. 400 W
3. 300 W
4. Zero
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