Advertisements
Advertisements
Question
The self inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as ______.
Options
l and A increase.
l decreases and A increases.
l increases and A decreases.
both l and A decrease.
Advertisements
Solution
The self inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as l decreases and A increases.
Explanation:
The self inductance L of a solenoid depends on various factor like geometry and magnetic permeability of the core material.
L = μrμ0 N2 Al
Where n = N/l (no. of turns per unit length)
- No. of turns: Larger the number of turns in solenoid, larger is its self inductance.
- Area of cross-section: Larger the area of cross-section of the solenoid, larger is its self inductance.
- Permeability of the core material. The self inductance of a solenoid increases μr times if it is wound over an iron core of relative permeability μr.
The long solenoid of cross-sectional area A and length l, having A turns, filled inside of the solenoid with a material of relative permeability (e.g., soft iron, which has a high value of relative permeability) then its self inductance is L = μrμ0 N2 A/l
So, the self inductance L of a solenoid increases as l decreases and A increases because L is directly proportional to the area and inversely proportional to length.
Important point: The self and mutual inductance of capacitance and resistance depend on the geometry of the devices as well as permittivity/ permeability of the medium.
APPEARS IN
RELATED QUESTIONS
Define the coefficient of self-induction.
Write the SI unit and dimention of of co-efficient of self induction
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 currents ?
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 ?
Derive the expression for the self-inductance of a long solenoid of cross sectional area A and length l, having n turns per unit length.
Define self inductance. Write its S.I. units.
Choose the correct option
A current through a coil of self-inductance 10 mH increases from 0 to 1 A in 0.1 s. What is the induced emf in the coil?
Obtain an expression for the self-inductance of a solenoid.
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 ______.
Magnetic flux of 12 microweber is linked with a coil. When current of 3 mA flows through it, the self inductance of the coil is ____________.
A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when ____________.
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 ______.
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 ______.
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 ______.
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:
What is meant by magnetic coupling coefficient?
A coil of self-inductance L is connected in series with a bulb and an a. c. source. Brightness of the bulb decreases when ______.
