**Mutual Induction**

The chapter on Faraday's law of electromagnetism is one of the most important chapters in JEE syllabus. Lots of problems are asked from this chapter not only in JEE, but also in other competitive exams including KVPY and Indian National Physics Olympiad. So, students are advised to study this chapter thoroughly.

Mutual Induction is an important part of this chapter. Students should understand the Faraday's laws of induction properly before moving on to self induction or mutual induction.

Most problems asked in JEE involve calculation of mutual inductance of a set of 2 conductors. Here are the steps to follow:

1. Understand the arrangement of the conductors properly. Try finding any symmetry. Look for radial and axial symmetries, which are most common in competitive examinations.

2. Now assume a unit current to be flowing in one of the conductors.

3. Calculate flux in the other conductor due to this conductor. Symmetry arguments will usually be helpful here. In the worst case, you might require an integration.

4. The value of the flux (for the unit current) gives you the value of mutual inductance between the pair of conductors (coils).

Students should also have a brief idea of the applications of mutual induction, which include Electric Generator, induction cooker, etc.

Where to read theory from?

1. Always start with NCERT text books. They will help you to get a feel of the topic

2. Always refer an advanced text book if you are aiming for a real understanding of the topic. Resnick Halliday Walker by Wiley Publishers is an excellent book for this. The book contains ample of theory with detailed examples for proper understanding

Where to practice problems from?

1. Practice problems from as many sources as possible. The more you practice, the better will you be at that particular concept. This applies not only to Mutual Induction, but also to all other topics in general.

2. Make sure to solve the in-text problems without seeing the solution directly. This way, you will be able to evaluate your understanding of what you just read.

3. There are a lot of end chapter problems in Resnick Halliday Walker. These problems have been designed in a way that helps you get a real understanding of the concept. Solve the problems carefully and you will definirely feel confident with the subject.

4. Do not limit yourself to a single book. Make sure to practice past year practice probblems of the competitive exam as well.

It is important to spend more time in doing problems which involve mutual inductance calculation, because this is generally the very first step to be done in a problem involving mutual induction. You should be familiar with most common results (parallel coils for example) and use these results directly in the examination to save time.

We hope that this article was helpful to you.

**About the Author**

Aman Goel is B.Tech, computer science and engineering undergraduate student at Indian Institute of Technology, Bombay. Born in a business oriented family of Kanpur he secured an All India Rank 33 in JEE advanced 2013 and also scored 323/360 in JEE main 2013. He has also cleared Indian National Physics and Chemistry Olympiads, and KVPY. In his free time, he likes to write articles related to JEE preparation. He loves speedcubing (the art of speed solving a Rubik's cube) and also loves to play computer/mobile games. |

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