Question
- 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.
✓
Answer
Self inductance: is defined as the magnetic flux passing through the coil when a unit current flows through it.Alternate Answer
It is the emf induced in the coil when the rate of change of current through it is unity.
SI Unit is henry
The magnetic field due to a current I flowing in the solenoid is $B =µ_0nI$ The total flux linked with the solenoid is NBA, i.e.
$\phi =\big(\text{nl}\big)\big(\mu_\circ\text{nI}\big)\text{A}$
$ = \mu_\circ\text{n}^{2}\ \text{IlA}$
$\text{L} =\frac{\phi}{\text{I}} =\mu_\circ\text{n}^{2} \text{Al}$
$ = \frac{\mu_\circ\text{N}^{2}\text{A}}{l}$
It is the emf induced in the coil when the rate of change of current through it is unity.
SI Unit is henry
The magnetic field due to a current I flowing in the solenoid is $B =µ_0nI$ The total flux linked with the solenoid is NBA, i.e.
$\phi =\big(\text{nl}\big)\big(\mu_\circ\text{nI}\big)\text{A}$
$ = \mu_\circ\text{n}^{2}\ \text{IlA}$
$\text{L} =\frac{\phi}{\text{I}} =\mu_\circ\text{n}^{2} \text{Al}$
$ = \frac{\mu_\circ\text{N}^{2}\text{A}}{l}$
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