Question

find the expression for mutual inductance between a pair of co-axial coils?​

Answer 1

The expression for mutual inductance between a pair of co-axial coils is:

• The ratio between magnetic flux passing through on coil to the current passing through coils is known as mutual inductance between two coils.
• The magnetic flux of two coils are Ф1 and Ф2 and therefore,

              Ф1 ⇒ i2

               N1Ф1 = M12i2

                M12 is the mutual inductance of 1 w.r.t 2.

                Ф1 = B2 A1 = U0n2i2(πr^2)

                N1 = n1L

                N1Ф1 = U0n1n2(πr^2)Li2

                M12 = N1Ф1/i2 = U0n1n2(πr^2)L.

             Where M is the constant of this couple of coils called co-efficient

             of mutual induction.

• Here N1 and N2 are the total number of turns in two solenoids and each of length L and r be the radii of co-axial solenoids.