Page 23 - Basics of Electrical, Electronic and Communication

54 Chapter 3. Magnetic circuits

Thus coefficient of coupling may be defined as the ratio of actual
mutual inductance present between the two coils to the maximum pos-
sible value of mutual inductance.

Example 1
Find the induced emf in a conductor when rotated in a uniform field of
magnetic flux 2 mWb in 0.02 s. Given number of turns of the conductor
is 100.

Solution
Given N = 100 turns
dΦ
Induced emf, e = −N
dt
2 × 10 −3
= −100 ×
0.02
0.002
= −100 × = −10 V
0.02

Example 2
A current of 5 A when flowing through a coil of 1000 turns, produces
a flux of 0.3 mWb. Determine the inductance of the coil.

Solution
Given,
I = 5 A
N = 1000 turns
Φ = 0.3 mWb = 0.3 × 10 −3 Wb
NΦ
We have, inductance of the coil, L =
I
1000 × 0.3 × 10 −3
= = 0.06 H
5

Example 3
A coil consists of 750 turns and a current of 10 A in coil produces a
magnetic flux of 1.2 mWb. Calculate the inductance of the coil. If the

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