Advertisements
Advertisements
प्रश्न
An inductor coil of some resistance is connected to an AC source. Which of the following quantities have zero average value over a cycle?
(a) Current
(b) Induced emf in the inductor
(c) Joule heat
(d) Magnetic energy stored in the inductor
उत्तर
(a) Current
(b) Induced emf in the inductor
For a series L-R circuit, the AC current can be given by,
From the graph, we can see that the average value of current over a cycle is zero.
Since it a series L-R circuit, the phase difference between current and voltage is `pi/2`. The AC voltage can be given by,
`V = V_0 cos omega t`
From the graph, we can see that the average value of voltage over a cycle is also zero.
Joule's heat through the resistor is given by,
`H_{avg} = i_rms^2 R , "which is non zero"`
Similarly, magnetic energy stored in the inductor is given by,
`U_{avg }= 1/2 Lirms^2 , "which is also non zero" `
APPEARS IN
संबंधित प्रश्न
An inductor, a resistance and a capacitor are joined in series with an AC source. As the frequency of the source is slightly increased from a very low value, the reactance
An inductance of 2.0 H, a capacitance of 18μF and a resistance of 10 kΩ is connected to an AC source of 20 V with adjustable frequency.
(a) What frequency should be chosen to maximize the current in the circuit?
(b) What is the value of this maximum current?
An inductor-coil, a capacitor and an AC source of rms voltage 24 V are connected in series. When the frequency of the source is varied, a maximum rms current of 6.0 A is observed. If this inductor coil is connected to a battery of emf 12 V and internal resistance 4.0 Ω, what will be the current?
Show that in an AC circuit containing a pure inductor, the voltage is ahead of current by π/2 in phase.
A 44 mH inductor is connected to 220 V, 50 Hz ac supply. Determine the rms value of the current in the circuit.
Obtain if the circuit is connected to a high-frequency supply (240 V, 10 kHz). Hence, explain the statement that at very high frequency, an inductor in a circuit nearly amounts to an open circuit. How does an inductor behave in a dc circuit after the steady state?
Obtain if the circuit is connected to a 110 V, 12 kHz supply? Hence, explain the statement that a capacitor is a conductor at very high frequencies. Compare this behaviour with that of a capacitor in a dc circuit after the steady state.
An applied voltage signal consists of a superposition of a dc voltage and an ac voltage of high frequency. The circuit consists of an inductor and a capacitor in series. Show that the dc signal will appear across C and the ac signal across L.
Alternating current is so called because _______.
Average power supplied to an inductor over one complete cycle is ______.
A current of 4A flows in a coil when connected to a 12V dc source. If the same coil is connected to a 12V, 50 rad/s a.c. source, a current of 2.4A flows in the circuit. Determine the inductance of the coil.
An inductor of inductance L, a capacitor of capacitance C and a resistor of resistance ‘R’ are connected in series to an ac source of potential difference ‘V’ volts as shown in the figure.
The potential difference across L, C, and R is 40 V, 10 V and 40 V, respectively. The amplitude of the current flowing through the LCR series circuit is `10sqrt2 "A"`. The impedance of the circuit is:
Explain why the reactance offered by an inductor increases with increasing frequency of an alternating voltage.
An ideal inductor is connected across an AC source of voltage. The current in the circuit ______.
Draw a phasor diagram showing e and i in the case of a purely inductive circuit. A 40-turn square coil of side 0.2 m is placed in a magnetic field of induction 0.05 T with the plane of the coil perpendicular to the direction of the field. If the magnetic induction is uniformly reduced to zero in 5 milliseconds, find the emf induced in the coil.
