Ecklectic Electrickery : Electromagnetism 101

So, cutting short to the essential matter… Electromagnetism covers the following chapters :

Chapter-Wise Analysis :

  • Electrostatics : The biggest chapter on electric phenomenon and perhaps the most involved. This chapter needs a crisp understanding of concepts and endless practice. Only then can it be handled well. A good news however is this…. If sufficient hard work is put in this chapter, and results are guaranteed. With about 5-7 chapters in JEE every year coming only from this chapter, it is something you definitely must not overlook. Gauss Theorem is extremely useful… learn to use it well. Certain relations, like the relation of Electric field intensity and electric potential, etc are useful. Additionally, solid angle concept is useful for a certain type of questions. Have a look over it for sure.
  • Current Electricity : The chapter completely based on circuit solutions. Not a tough chapter. Know how to apply KVL and KCL well (Kirchoff’s Laws) and you shall be able to solve about 90% of problems from this chapter. Note that solving problems of this chapter also requires some intuition. Hence, practice is essential. Current density is an important concept too. Many questions use Maximum Power Transfer theorem. However, i do not recommend it as we forget the conditions under which it is applied. Differentiation is slower but surer.
  • Capacitance : A relatively easy chapter if you have prepared electrostatics and current electricity well. All the circuit solving techniques of the previous chapter apply here, including the famous Wheatstone bridge. Also, tricks like… capacitor is short circuit at t=0 and is open circuit after infinitely long time are quite useful.
  • Magnetic Effects of Current : With this chapter, magnetism enters the game. Make sure that you are good at finding directions when vectors are crossed with each other (AxB). Biot Savart law is useful for any general case but most questions tend not to use it. Rather, Ampere’s Circuital Law is used extensively in many analysis, like even those of torus. F=q(v cross B) is an important formula that you should remember given that it does not have any derivation as such.
  • EMI (ElectroMagnetic Induction) : Important and a tough chapter, one that took me almost 6 months to master. There are loads of relations in this chapter which can be used. However, certain relations are very useful to solve questions and one of those is the induced looped electric field due to change of magnetic flux through the coil. This result particularly helps in solving dynamics questions, even those that ask about induced currents. Additionally, transformers are important although easy. Lenz law is perhaps the most important concept of this chapter and it explains almost everything we use in this chapter. Self inductance and mutual inductance are quite important.
  • AC Circuits : This might not be a chapter. However, i felt that it should be dealt with separately as it is effectively quite important for JEE. Differential equation approach is out if syllabus here. However, we are gonna use phasor vector methods here to do the necessary solutions. Resonance conditions, quality factor etc are important specially for JEE Main.

Books : 

  • H.C. Verma Concepts of Physics Vol. 2 is very useful to get concepts clarified at beginning stages of electromagnetism.
  • I E Irodov might be useful for electromagnetism, especially while preparing for olympiads. However, i never needed it.
  • Coaching material is useful here as it is relevant and concise.

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