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प्रश्न
Define self-inductance.
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उत्तर
The self-inductance of a circuit is the ratio of magnetic flux (produced due to current in the circuit) linked with the circuit to the current flowing in it.
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संबंधित प्रश्न
In a given coil of self-inductance of 5 mH, current changes from 4 A to 1 A in 30 ms. Calculate the emf induced in the coil.
Current in a circuit falls from 5.0 A to 0.0 A in 0.1 s. If an average emf of 200 V induced, give an estimate of the self-inductance of the circuit.
Define self-inductance. Write its SI units.
Define self-inductance of a coil. Show that magnetic energy required to build up the current I in a coil of self inductance L is given by `1/2 LI^2`
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.
Consider the self-inductance per unit length of a solenoid at its centre and that near its ends. Which of the two is greater?
A constant current i is maintained in a solenoid. Which of the following quantities will increase if an iron rod is inserted in the solenoid along its axis?
(a) magnetic field at the centre
(b) magnetic flux linked with the solenoid
(c) self-inductance of the solenoid
(d) rate of Joule heating.
Two solenoids have identical geometrical construction but one is made of thick wire and the other of thin wire. Which of the following quantities are different for the two solenoids?
(a) self-inductance
(b) rate of Joule heating if the same current goes through them
(c) magnetic field energy if the same current goes through them
(d) time constant if one solenoid is connected to one battery and the other is connected to another battery.
A magnetic flux of 8 × 10−4 weber is linked with each turn of a 200-turn coil when there is an electric current of 4 A in it. Calculate the self-inductance of the coil.
A coil having inductance 2.0 H and resistance 20 Ω is connected to a battery of emf 4.0 V. Find (a) the current at the instant 0.20 s after the connection is made and (b) the magnetic field energy at this instant.
An inductor of inductance 5.0 H, having a negligible resistance, is connected in series with a 100 Ω resistor and a battery of emf 2.0 V. Find the potential difference across the resistor 20 ms after the circuit is switched on.
What are the values of the self-induced emf in the circuit of the previous problem at the times indicated therein?
Explain why the inductance of two coils connected in parallel is less than the inductance of either coil.
Two pure inductors each of self-inductance L are connected in series, the net inductance is ______
Obtain an expression for the self-inductance of a solenoid.
Two rods of same material and volume having circular cross-section are subjected to tension T. Within the elastic limit, same force is applied to both the rods. Diameter of the first rod is half of the second rod, then the extensions of first rod to second rod will be in the ratio
The coefficient of self-inductance of a solenoid is 0.20 mH. If a core of soft iron of relative permeability 900 is inserted, then the coefficient of self-inductance will become nearly ______
The magnetic potential energy stored in a certain inductor is 15 mJ, when the current in the inductor is 40 mA. This inductor is of inductance ____________.
Consider a solenoid carrying supplied by a source with a constant emf containing iron core inside it. When the core is pulled out of the solenoid, the change in current will ______.
An e.m.f. of 10 volt is produced by a self inductance when the current changes at a steady rate from 6 A to 4 A in 1 millisecond. The value of self inductance is ____________.
Two coils of wire A and B are placed mutually perpendicular as shown. When current is changed in any one coil.
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 graph of magnetic flux `phi` versus current (I) is shown for four inductors A, B, C, D. Smaller value of self inductance is for inductor ____________.
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 ____________.
A graph of magnetic flux `(phi)` versus current (I) is shown for four inductors A, B, C and D. Larger value of self-inductance is for inductor ____________.
Two coils of self inductances 2 mH and 8 mH are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is ______.
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 ______.
When current i passes through an inductor of self-inductance L, energy stored in it is 1/2. L i2. This is stored in the ______.
The self-inductance associated with a coil is independent of ______.
If both the number of turns and core length of an inductor is doubled keeping other factors constant, then its self-inductance will be ______.
Energy needed to establish an alternating current I in a coil of self-inductance L is
What is the unit of self-inductance of a coil?
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:
An average induced emf of 0.20 V appears in a coil when the current in it is changed from 5A in one direction to 5A in the opposite direction in 0.20 sec. Find the self induction of the coil.
The self-inductance depends upon ______.
Consider an infinitely long wire carrying a current I(t), with `(dI)/(dt) = λ` = constant. Find the current produced in the rectangular loop of wire ABCD if its resistance is R (Figure).
Calculate the self-inductance of a coil using the following data obtained when an AC source of frequency `(200/pi)` Hz and a DC source are applied across the coil.
| AC Source | ||
| S.No. | V (volts) | I (A) |
| 1 | 3.0 | 0.5 |
| 2 | 6.0 | 1.0 |
| 3 | 9.0 | 1.5 |
| DC Source | ||
| S.No. | V (volts) | I (A) |
| 1 | 4.0 | 1.0 |
| 2 | 6.0 | 1.5 |
| 3 | 8.0 | 2.0 |
A current of 1A flows through a coil when it is connected across a DC battery of 100V. If the DC battery is replaced by an AC source of 100 V and angular frequency of 100 rad s-1, the current reduces to 0.5 A. Find
- the impedance of the circuit.
- self-inductance of coil.
- Phase difference between the voltage and the current.
Obtain an expression for the self inductance of a solenoid.
What is meant by magnetic coupling coefficient?
Two inductor coils with inductance 5 mH and 15 mH are connected in parallel. The resultant inductance of the combination of the two coils is ______.
