A capacitor in an LC oscillator has a maximum potential difference of 17 V and a maximum energy of 160 μJ. When the capacitor has a potential difference of 5 V and an energy of 10μJ, what is the energy stored in the magnetic field ?
If we increase the driving frequency in a circuit with apurely resistive load, then amplitude VR
The figure shows a sine curve S(t) = sinωt and three other sinusoidal curves A(t), B(t) and C(t), each of the form sin (ωt - ). Which curve is according to the most negative value off.
A parallel-plate capacitor with rectangular plates is being discharged. A rectangular loop, centered on the plates and between them, measures L by 2L : the plates measure 2L by 4L. The fraction of the displacement current is encircled by the loop if that current is uniform
Figure shows three oscillating LC circuit with identical inductors and capacitors. If t1, t2, t3 are the time taken by the circuits I, II, III for fully discharge, then
In an oscillating LC circuit with L = 50 mH and C = 4.0 μF, the current is initially a maximum. How long will it take before the capacitor is fully discharged for the first time :
Charges on the capacitors in three oscillating LC circuits vary as follows (1) q = 2 cos 4t. (2) q = 4cos t, (3) q = 3 cos 4t, (4) q = 4 cos 2t, with q in coulomb and t in second. In which circuit (s) current amplitude is greatest:
A charged capacitor and an inductor are connected in series at time t = 0. Read the statements :
(1) the charge on the capacitor is zero after a time T/2
(2) The charge on the capacitor is zero after time T/4
(3) the energy stored in the capacitor maximum at T/2
(4) the energy stored in the inductor is maximum at T/4
If we increase the driving frequency in a circuit with a purely capacitive load. Read the following statements
(1) amplitude Vc increases
(2) amplitude Vc decrease
(3) amplitude ic increase
(4) amplitude ic decreases
Out of these, the correct statement(s) is/are
If we increase the deriving frequency in a circuit with a purely inductive load. Read the following statements :
(1) amplitude VL remain constant
(2) amplitude VL increases
(3) amplitude iL increases
(4) amplitude iL decreases
Out of these, the correct statement (s) is / are
Here are the capacitive reactance and inductive reactance, respectively, for three sinusoidally driven
RLC circuits : (1) 50 W, 100 W (2) 100 W, 50 W (3) 100 W,100 W
Which is in resonance ?
An alternating current emf device has a smaller resistance than that of the resistive load, to increase the transfer of energy from the device to the load, a transformer will be connected between two. Then
The figure here gives the electric field of an electromagnetic wave at a certain point and a certain instant. The wave is transporting energy in the negative z-direction. The direction of the magnetic field of the wave at that point and instant is :
Which of the following plots may represent the eactance of a series LC combination ?
An AC source is rated 220 V, 50 Hz. The average voltage is calculated in a time interval of 0.01s. It
An electromagnetic wave going through vacum is described by E = E0 sin (kx-ωt) ; B = B0 sin (kx-ωt) .
Alternating current can not be measured by dc ammeterbecause
If a current I given by I0 flows in an ac circuit across which an ac potential of V = V0 sinωt has been applied, then the power consumption P in the circuit will be
An alternating voltage V = 200√2 sin(100t) is connected to a 1 microfarad capacitor through an ac ammeter. The reading of the ammeter shall be
A 220 V, 50 Hz ac source is connected to an inductance of 0.2 H and a resistance of 20 ohm in series. What is the current in the circuit?
In the circuit shown below, the ac source has voltage V = 20 cos(ωt ) volt with ω = 2000 rad/s. the amplitude of the current will be nearest to
The power factor of an ac circuit having resistance (R) and inductance (L) connected in series and an angular velocity ω is
An inductor of inductance L and resistor of resistance R are joined in series and connected by a source of frequency ω . Power dissipated in the circuit is
In a LCR circuit capacitance is changed from C to 2C. For the resonant frequency to remain unchanged, the nductance should be change from L to
In an LCR series ac circuit, the voltage across each of the components, L, C and R is 50 V. The voltage across the LC combination will be
A bulb and a capacitor are connected in series to a source of alternating current. If its frequency is increased, while keeping the voltage of the source constant, then
An alternating e.m.f. of angular frequency ω is applied across an inductance. The instantaneous power developed in the circuit has an angular frequency
The diagram shows a capacitor C and a resistor R connected in series to an ac source. V1 and V2 are voltmeters and A is an ammeter.
Consider now the following statements
I. Readings in A and V2 are always in phase
II. Reading in V1 is ahead in phase with reading in V2
III. Readings in A and V1 are always in phass.
Which of these statements are/is correct?
The voltage of an ac supply varies with time (t) as V = 120 sin100πtcos100 πt . The maximum voltage and frequency respectively are
Match the following
An ac source of angular frequency ω is fed across a resistor r and a capacitor C in series. The current registered is I. If now the frequency of source is changed to ω / 3 (but maintaining the same voltage), the current in the circuit is found to be halved. Calculate the ratio of reactance to resistance at the original frequency ω
The output current versus time curve of a rectifier is shown in the figure. The average value of output current in this case is
When an ac source of e.m.f. e = V0 sin(100t) is connected across a circuit, the phase difference between the e.m.f. e and the current i in the circuit is observed to be π / 4, as shown in the diagram If the circuit consists possibly only of RC or LC in series, find the relationship between the two elements
In an oscillatory circuit, L = 0.4 H, C = 0.0024 μF. Themaximum value of the resistance that should be included is:
At t < 0, the capacitor is charged and the switch is opened. At t = 0 the switch is closed. The shortest time T at which the charge on the capacitor will be zero is given by :