Let F1 be the flux through coil C1 (say of N1 turns) when current in
coil C2 is I2 Then, from Eq (6 7), we have
N1F1 = MI2
For currents varrying with time,
(
)
(
)
1
1
2
d
d
d
d
N
MI
t
t
Φ
=
Since induced emf in coil C1 is given by
(
)
1
1
–d
d
N
t
Φ
ε1 =
We get,
d2
–
Id
M
t
ε1 =
Rationalised 2023-24
Physics
168
It shows that varying current in a coil can induce emf in a neighbouring
coil