हिंदी

Explain why the inductance of two coils connected in parallel is less than the inductance of either coil.

Advertisements
Advertisements

प्रश्न

Explain why the inductance of two coils connected in parallel is less than the inductance of either coil.

टिप्पणी लिखिए
Advertisements

उत्तर १

  1. For a parallel combination of two coils, the current through each parallel inductor is a fraction of the total current and the voltage across each parallel inductor is the same.
  2. As a result, a change in total current will result in less voltage dropped across the parallel array than for any one of the individual inductors.
  3. There will be less voltage drop across parallel inductors for a given rate of change in current than for any of the individual inductors.
  4. Less voltage for the same rate of change in current results in less inductance.
  5. Thus, the total inductance of two coils is less than the inductance of either coil.
shaalaa.com

उत्तर २

When two inductors with inductances L1 and L2 are connected in parallel, the equivalent inductance is given by

`1/"L"_"equivalent" = 1/"L"_1 + 1/"L"_2`

which is less than the individual inductance value L1 and L2.

As a result, the inductance of two parallel coils is smaller than the inductance of either coil.

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 12: Electromagnetic Induction - Short Answer I

APPEARS IN

बालभारती Physics [English] Standard 12 Maharashtra State Board
अध्याय 12 Electromagnetic induction
Exercises | Q 2.5 | पृष्ठ २८६

संबंधित प्रश्न

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 the coefficient of self-induction.


Define self-inductance. Write its SI units.


A toroidal solenoid with air core has an average radius of 15 cm, area of cross-section 12 cm2 and has 1200 turns. Calculate the self-inductance of the toroid. Assume the field to be uniform across the cross-section of the toroid.


The currents flowing in the two coils of self-inductance L1 = 16 mH and L2 = 12 mH are increasing at the same rate. If the power supplied to the two coil is equal, find the ratio of the energies stored in the two coils at a given instant ?


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?


Define self inductance. Write its S.I. units.


Derive an expression for self inductance of a long solenoid of length l, cross-sectional area A having N number of turns.


An average emf of 20 V is induced in an inductor when the current in it is changed from 2.5 A in one direction to the same value in the opposite direction in 0.1 s. Find the self-inductance of the inductor.


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.


An inductor-coil carries a steady-state current of 2.0 A when connected across an ideal battery of emf 4.0 V. If its inductance is 1.0 H, find the time constant of the circuit.


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.


Two pure inductors each of self-inductance L are connected in series, the net inductance is ______  


When a coil is connected to a D.C. source of e.m.f. 12 volt, then a current of 4 ampere flows in it. If the same coil is connected to a 12 volt, 25 cycle/s A.C sources, then the current flowing in it is 2.4 A. The self-inductance of the coil will be ______


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 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 ______.


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 ____________.


When the current in a coil changes from 2 amp. to 4 amp. in 0.05 sec., an e.m.f. of 8 volt is induced in the coil. The coefficient of self inductance of the coil is ______.


A coil is wound on a frame of rectangular cross-section. If all the linear dimensions of the frame are increased by a factor 2 and the number of turns per unit length of the coil remains the same, self-inductance of the coil increases by a factor of ______.


The self-inductance of a coil is a measure of ______.

The self-inductance associated with a coil is independent of ______.

An inductor may store energy in


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:


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).


The inductance of a solenoid L having diameter d. Let n be the number of turns per unit length. The inductance per unit length near the middle of a solenoid is ______.

(Assume that, l = current passes through the turns, µ0 = Permeability of vacuum)


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

  1. the impedance of the circuit.
  2. self-inductance of coil.
  3. Phase difference between the voltage and the current.

An air-cored solenoid, 40 cm long and of cross-sectional area 5 cm2, is tightly wound with 400 turns of copper wire and carries a steady current of 10 A. (a) Calculate the self-inductance of the solenoid. (b) Find the emf induced if the current in the solenoid decreases to zero in 0.2 s.


Obtain an expression for the self inductance of a solenoid.


A toroid of a circular cross-section of radius 0.05 m has 2000 windings and a self-inductance of 0.04 H. What is (a) the current through the windings when the energy in its magnetic field is 2 × 10−6 J and (b) the central radius of the toroid?


What is meant by magnetic coupling coefficient?


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


In a coil, the current changes form −2 A to +2 A in 0.2 s and induces an emf of 0.1 V. The selfinductance of the coil is ______.


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 ______.


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:






Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×