The power factor of the given circuit is:
1. | \(1 \over 2\) | 2. | \(1 \over \sqrt2\) |
3. | \(\sqrt3 \over 2\) | 4. | \(0\) |
The power factor of a series LCR circuit in resonance condition is:
What is the instantaneous power of a resistor having resistance R across an ac supply of E=E0sin ωt?
In a step-up transformer, the turn ratio is 1: 20. The resistance of 100 connected across the secondary is drawing a current of 2 A. What are the primary voltage and current respectively?
1. 100 V, 0.5 A
2. 200 V, 10 A
3. 10 V, 40 A
4. 10 v, 20 A
Voltage and current in an ac circuit are given by \(V=5sin\left ( 100\pi t-\frac{\pi }{6}~ \right )~V\) and \(I=4sin\left ( 100\pi t+\frac{\pi }{6}~ \right )~A.\)
Hence:
1. | The voltage leads the current by 30°. |
2. | The current leads the voltage by 30°. |
3. | The current leads the voltage by 60°. |
4. | The voltage leads the current by 60°. |
An alternating voltage (in volts) given by \(V=200\sqrt{2}sin100t\) is connected to a\(1~\mu F\) capacitor through an \(ac\) ammeter. The reading of the ammeter will be:
1. | \(10~ \mathrm{mA}\) | 2. | \(20~ \mathrm{mA}\) |
3. | \(40~ \mathrm{mA}\) | 4. | \(80~ \mathrm{mA}\) |
It is found that the current through the LCR series circuit is at its maximum. If are potential differences across resistance, capacitor, and inductor respectively, then which of the following is correct?
1. | \(V_r=V_L>V_C\) |
2. | \(V_R \neq V_L=V_C\) |
3. | \(V_R \neq V_L \neq V_C\) |
4. | \(V_R=V_C \neq V_L\) |
In a series LCR circuit, the current through the ac source is 2 A. If resistor R has a resistance of 10 Ω, the average power dissipated in the circuit is:
1. 20 W
2. 30 W
3. 10 W
4. 40 W
A capacitor of capacitance 1 is charged to a potential of 1 V. It is connected in parallel to an inductor of inductance H. What is the value of the maximum current that will flow in the circuit?
In a box Z of unknown elements (L or R or any other combination), an ac voltage is applied and the current in the circuit is found to be . The unknown elements in the box could be:
1. | Only the capacitor |
2. | Inductor and resistor both |
3. | Either capacitor, resistor, and an inductor or only capacitor and resistor |
4. | Only the resistor |