Advertisements
Advertisements
प्रश्न
An ideal inductor is connected across an AC source of voltage. The current in the circuit ______.
विकल्प
is ahead of the voltage in phase by π.
lags voltage in phase by π.
is ahead of voltage in phase by `pi"/"2`.
lags voltage in phase by `pi"/"2`.
Advertisements
उत्तर
An ideal inductor is connected across an AC source of voltage. The current in the circuit `underlinebb("lags voltage in phase by "pi"/"2)`.
Explanation:
`epsi = (-LdI)/(dt)`
`epsi_0 sinomegat = (-LdI)/(dt)`
In magnitude `(dI)/(dt) = epsi_0/L sinomegat`
On integrating both sides,
I = `intepsi_0/L sinomegat dt`
I = `epsi_0/L ((-1)/omega cosomegat)`
I = `-epsi_0/(Lomega) (cos omegat)`
I = `-epsi_0/(Lomega) sin(pi/2 - omegat)`
= `epsi_0/(Lomega) sin(omegat - pi/2)`
I = `I_0 sin(omegat - pi/2)`
Hence, current lags voltage in phase π/2.
APPEARS IN
संबंधित प्रश्न
A coil of inductance 0.50 H and resistance 100 Ω is connected to a 240 V, 50 Hz ac supply.
(a) What is the maximum current in the coil?
(b) What is the time lag between the voltage maximum and the current maximum?
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?
Alternating current is so called because _______.
Average power supplied to an inductor over one complete cycle is ______.
If the frequency of an A.C. is made 4 times of its initial value, the inductive reactance will ______.
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 ac voltage V = V0 sin ωt is applied across a pure inductor of inductance L. Find an expression for the current i, flowing in the circuit and show mathematically that the current flowing through it lags behind the applied voltage by a phase angle of `π/2`. Also draw graphs of V and i versus ωt for 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.
