Advertisements
Advertisements
प्रश्न
When the frequency of the AC source in an LCR circuit equals the resonant frequency, the reactance of the circuit is zero. Does it mean that there is no current through the inductor or the capacitor?
Advertisements
उत्तर
The condition for resonance is:
`1/(omegaC) = omegaL`
The peak current through the circuit is given by,
`i_0 = (V_0)/sqrt(R^2 + (1/(omegaC - omegaL))^2`
From the condition of resonance, we get:
`i_0 = (V_0)/R`
The current will flow through the all circuit elements. But since the reactance of the capacitor and inductor are equal, the potential difference across them will be equal and opposite and will cancel each other.
APPEARS IN
संबंधित प्रश्न
Draw a graph to show variation of capacitive-reactance with frequency in an a.c. circuit.
An inductor L of inductance XL is connected in series with a bulb B and an ac source. How would brightness of the bulb change when (i) number of turn in the inductor is reduced, (ii) an iron rod is inserted in the inductor and (iii) a capacitor of reactance XC = XL is inserted in series in the circuit? Justify your answer in each case.
Three capacitors of capacities 8 μF, 8 μF and 4 μF are connected in a series and potential difference of 120 volt is maintained across the combination. Calculate the charge on capacitor of capacity 4 μF.
A capacitor of capacitance 0.5 μF is connected to a source of alternating e.m.f. of frequency 100 Hz. What is the capacitive reactance? (Π = 3.142)
A light bulb and a solenoid are connected in series across an ac source of voltage. Explain, how the glow of the light bulb will be affected when an iron rod is inserted in the solenoid.
A light bulb is rated at 100 W for a 220 V a.c. supply. Calculate the resistance of the bulb.
A light bulb is rated at 120 W for a 220 V a.c. supply. Calculate the resistance of the bulb.
A light bulb is rated 100 W for 220 V ac supply of 50 Hz. Calculate
(i) The resistance of the bulb;
(ii) The rms current through the bulb.
What is the reactance of a capacitor connected to a constant DC source?
Which of the following plots may represent the reactance of a series LC combination?
(i) An alternating emf of 200 V, 50 Hz is applied to an L-R ciruit, having a resistance R of 10 Ω and an inductance L of 0.05H connected in series. Calculate :
(1) Impedance
(2) Current flowing in the circuit
(ii) Draw a labelled graph showing the variation of inductive reactance (`X_L`) verses frequency (`f`) .
A coil having self-inductance of 0.7 H and resistance of 165 Ω is connected to an a.c. source of
275V,50Hz. If π = `22/7`
Calculate:
(i) Reactance of the coil
(ii) Impedance of the coil ‘
(iii) Current flowing through the coil
Which of the following graphs represents the correct variation of inductive reactance XL with frequency u?
In a pure capacitive circuit if the frequency of ac source is doubled, then its capacitive reactance will be ______.
Which of the following graphs represents the correct variation of capacitive reactance Xc with frequency v u?
