Advertisements
Advertisements
प्रश्न
Answer the following question.
When an inductor is connected to a 200 V dc voltage, a current at 1A flows through it. When the same inductor is connected to a 200 V, 50 Hz ac source, only 0.5 A current flows. Explain, why? Also, calculate the self-inductance of the inductor.
Advertisements
उत्तर
When the inductor is connected across the 200 V DC circuit 1 A current flows because in this case the inductor simply acts as a resistor and there is no inductive reactance. Whereas, when we connect the same inductor across 200 V AC, due to inductive reactance the overall impedance is changed and hence the value of current also changes.
When the inductor is connected across 200 V DC
The resistance of the coil
`R = 200/1 = 200 Ω`
Let the self-inductance of the inductor be L,
When the inductor is connected across 200 V A.C.
Net impedance, Z = `sqrt((2pifL)^2 + R^2) = 200/0.5 = 400 Omega`
⇒ `(2pi xx 50 xx L)^2 + 200^2 = 400^2`
⇒ `(100piL)^2 = 160000 - 40000`
⇒ `10000pi^2L^2 = 120000`
⇒ `L^2 = 12/pi^2`
`therefore L = sqrt(12)/pi H`
संबंधित प्रश्न
A plot of magnetic flux (Φ) versus current (I) is shown in the figure for two inductors A and Β. Which of the two has larger value of self inductance?
Derive an expression for self inductance of a long solenoid of length l, cross-sectional area A having N number of turns.
A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when ____________.
A resistance of 100 `Omega`, inductor of self-inductance`(4/pi^2)` H and a capacitor of unknown capacitance are connected in series to an a.c. source of 200 V and 50 Hz. When the current and voltage are in phase, the capacitance and power dissipated is respectively ____________.
The coefficient of self inductance of a solenoid is 0.18 mH. If a core of soft iron of relative permeability 900 is inserted, then the coefficient of self inductance will become nearly ______.
Two solenoids of same cross-sectional area have their lengths and number of turns in ratio of 1 : 2 both. The ratio of self-inductance of two solenoids is ______.
A coil of wire of a certain radius has 600 turns and a self-inductance is 108 mH. The self-inductance of a second similar coil of 500 turns will be:
State the factors on which the magnetic coupling coefficient of two coils depends.
The current flowing through an inductor of self-inductance L is continuously increasing at constant rate. The variation of induced e.m.f. (e) verses dI/dt is shown graphically by figure
The current flowing through an inductor of self inductance ‘L’ is continuously increasing at constant rate. The variation of induced e.m.f. (e) versus `((dI)/(dt))`is shown graphically by:
