Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?
1.
2.
3.
4.
The potential differences across the resistance, capacitance and inductance are \(80\) V, \(40\) V and \(100\) V respectively in an \(LCR\) circuit.
What is the power factor of this circuit?
1. \(0.4\)
2. \(0.5\)
3. \(0.8\)
4. \(1.0\)
A 100 resistance and a capacitor of 100 reactance are connected in series across a 220 V source. When the capacitor is 50% charged, the peak value of the displacement current is
1. 2.2 A
2. 11A
3. 4.4A
4. 11A
A small-signal voltage V(t)=Vo sinωt is applied across an ideal capacitor C
(1) over a full cycle, the capacitor C does not consume any energy from the voltage source
(2) current I(t) is in phase with voltage V(t)
(3) current I(t) leads voltage V(t) by 180°
(4) current I(t) lags voltage V(t) by 90°
A transformer having efficiency of 90% is working on 200 V and 3 kW power supply. If the current in the secondary coil is 6A, the voltage across the secondary coil and the current in the primary coil respectively are
1. 300V,15A
2. 450V,15A
3. 450V,13.5A
4. 600V,15A
1. | Frequency of the AC source is decreased |
2. | The number of turns in the coil is reduced |
3. | A capacitance of reactance \(X_C = X_L\) is included in the same circuit |
4. | An iron rod is inserted in the coil |
In an electrical circuit R, L, C, and an AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and the current in the circuit is If instead, C is removed from the circuit, the phase difference is again The power factor of the circuit is
(1) 1/2
(2) 1/
(3) 1
(4)
The instantaneous values of alternating
current and voltages in a circuit are given
as
The average power in Watts consumed in the
circuit is
(a)
(b)
(c)
(d)
In an AC circuit an alternating voltage volt is connected to a capacitor The value of the current in the circuit is
(a) 100 mA
(b) 200 mA
(c) 20 mA
(d) 10 mA
The current i in a coil varies with time as shown in the figure. The variation of induced emf with time would be
(a) (b)
(c) (d)