- Consider a long solenoid of length l and area of crossection A containing N
_{p}turns in its primary coil

- Let a shorter secondary coil having N
_{2}number of turns be wounded closely over the central portion of primary coil as shown below in the figure.

- If I
_{p}is the current in the primary coil then magnetic field due to primary coil would be

- So flux through each turn of secondary coil would be

where A is the area of crossection of primary coil

- Total magnetic flux through secondary coil is

- Emf induced in secondary coil is

Thus from equation 24

So

- Consider two coils of same length l and same area of cross-section placed near each other as shown below in the figure

- Let there are N
_{1}number of turns in primary coil and N_{2}number of turns in secondary coil

- A current I
_{1}in the primary coil produces a magnetic field

which in turns gives rise to flux?

in primary coil and

in the secondary coil due to current in primary coil.

- By the definition of self induction

and by definition of mutual induction

- Reversing the procedure if we first introduce the current I
_{2}in secondary coil then we get

- So L
_{1}is the self inductance of primary coil,L_{2}is the self induction of secondary coil and M_{21}=M_{12}=M is the mutual inductance between two coils

- Product of L
_{1}and L_{2}is

- In practice M is always less than eq due to leakage which gives

Where K is called coefficient of coupling and K is always less then 1.

Class 12 Maths Class 12 Physics

- NCERT Solutions: Physics 12th
- NCERT Exemplar Problems: Solutions Physics Class 12
- Concepts of Physics - Vol. 2 HC Verma
- Dinesh New Millennium Physics Class -XII (Set of 2 Vols) (Free Complete Solutions to NCERT Textbook Problems & NCERT Exemplar Problems in Physics-XII)
- Principles of Physics Extended (International Student Version) (WSE)
- university physics with modern physics by Hugh D. Young 13th edition
- CBSE Chapterwise Questions-Solutions Physics, Class 12
- CBSE 15 Sample Question Paper: Physics for Class 12th

- ncert solutions for class 6 Science
- ncert solutions for class 6 Maths
- ncert solutions for class 7 Science
- ncert solutions for class 7 Maths
- ncert solutions for class 8 Science
- ncert solutions for class 8 Maths
- ncert solutions for class 9 Science
- ncert solutions for class 9 Maths
- ncert solutions for class 10 Science
- ncert solutions for class 10 Maths