Self Inductance of Coil
Self Inductance of Coil
Self Inductance of Coil
ACKNOWLEDGEMENT
Siddhant Sah
XII-C
Certificate
This is to certify that, the project on the topic To study
________________________
Examiners signature
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principal
Experiment
Aim:
Apparatus Required:
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
Theory:
Self Inductance:
It is a phenomenon where growth and decay of
current is opposed due to change in magnetic
flux between diff. layers of a coil, there is a self
induced emf developed which opposes the
source emf.
I
t
t
Or,
= L I
, where L is a
t
t
constant of
proportionality called Coefficient of Self
Inductance.
From Laws of Electromagnetic Induction,
E = -L
t
Thus, self induction is Self Induced EMF developed due
to rate of change of current.
Suppose we have an Inductor(solenoid) of length L
having no of turns N connected to a source where
current is 0 at t=0, then due to change of flux, a local
emf is developed,
= L.I
..(1)
Again,
=BNA,
For a Solenoid,
B= oNI
l
Thus,
=
Equating 1 and 2,
2
L=
0 N A
l
0 N 2 IA
l
. (2)
Circuit Diagram:
Procedure:
Made all the connections as shown in the circuit
diagram.
Switched on the AC supply and adjusted the
constant current in the circuit by using the rheostat.
Recorded the current in AC ammeter and checked
the brightness of the bulb
The soft iron rod was put inside the inductor and the
current passing through the ammeter was recorded.
The current and Brightness both decreases.
Switched off the supply and decreased the
frequency of the AC source.
Again switched on the supply and adjusted the
current in the circuit at a constant voltage by using
a rheostat. Noted the readings of the ammeter and
checked the brightness of the bulb. The current and
the brightness decreases.
Again inserted the iron rod in the core and noted
the current and observed the brightness of the bulb.
Both decrease.
Observations:
1.
2.
3.
4.
5.
FREQUENCY
APPLIED
VOLTAGE
60
50
40
30
20
OF CURRENT
AMMETER
WITHOUT
ROD
2
2.5
2.9
3.4
4.1
IN CURRENT
AMMETER
IRON IRON ROD
IN
WITH
1.8
2.3
2.6
3.25
4
Result:
Precautions:
a. The coil should have large no. of turns.
b. Current should be passed for a small time to
avoid the heating effect.
Sources of Error:
The resistance
of
circuit
may
increase
BIBLIOGRAPHY
COMPREHENSIVE LABORATORY MANUAL OF Physics
APC Publication
WEBSITES
www.icbse.com
www.google.com
www.wikipedia.com