# EMT: Should I Study or Leave This Subject for GATE Exam?

Hi Guys,

Since GATE exam is approaching you must be thinking which subject you should study and which one you should leave. And I am sure many of you must be thinking to leave Electromagnetic Theory (EMT) for GATE. Right?

So today I will discuss with you all the strategy to prepare EMT for GATE exam.

But before that let us know what is the main reason that most of you tend to skip EMT for GATE Preparation. There could be two possible reasons:

First, this subject seems so difficult is that its roots lie in the Physics for Class 12th. Many of us were not very good at the concepts taught in Class 12th and hence find difficulty in this topic.

Second, this topic used to take around 6 months to cover in Class 12th but now we hardly have 10 days to cover the same number of concepts. We also have to cover the entire **GATE course** over a span of 6 months.

You can prepare the complete GATE syllabus yourself by referring to our video lectures for GATE (ECE).

Now let us discuss the importance of EMT from GATE point of view. This subject accounts for approximately 4-6 marks so it is no more insignificant and it is a very basic subject. If you have a thorough idea of this subject then you can easily crack questions based on this chapter.

Also, this subject forms the backbone of Electrical Engineering and the entire stream of Electrical Engineering has originated from this subject. The laws that are studied here are so fundamental that even Network Analysis laws have been derived from here. So, if you do not understand the laws of Electromagnetism then you lack the thorough knowledge of Electrical Engineering. Also, understanding the operation of Electrical Machines is impossible without the understanding of the laws of Electromagnetism. The books that you can follow for this subject include “Electromagnetic Theory (EMT) by SP Seth” and for problem-solving, you can use any 12th standard textbook.

Let us now go into details of this subject and understand what needs to be studied. And trust me if you will follow this strategy to prepare EMT for GATE exam then you will never find it difficult to cover it.

**Vector Analysis**

This chapter forms the mathematical infrastructure to understand the laws of EMT. In this chapter, first, you have to understand the basic laws of vectors such as the representation of vectors and vector algebra such as Vector Addition, Vector Subtraction using laws such as Triangle Law, Parallelogram Law, and Component Method. Then you have to study about other operations such as Dot Product, Cross Product, Scalar Triple Product, and Vector Triple Product.

Then you have to study advanced concepts such as different coordinate systems like Rectangular Co-ordinates, Cylindrical Co-ordinates, and Spherical Co-ordinates. You have to understand the conversion of units vectors between different coordinate systems and also the conversion of any vector between different systems. This understanding helps a lot because some problems might be easier to solve in one coordinate system as compared to others.

Then we proceed to Vector Calculus where we study about the differential operator (nabla) and understand different operations such as Gradient, Divergence, and Curl. You have to study the physical significance of these operations as well as the implementation in different coordinate systems. Then we proceed to Vector Integrals and we study about different theorems in Vector Integration such as Green’s Theorem, Stoke’s Theorem and Gauss Theorem. These concepts are covered in Engineering Mathematics as well but here you have to study about all coordinate systems and not just Rectangular Co-ordinates.

**Electrostatics**

This is the first chapter of EMT and is the widest topic. But at the same time, it is easy to understand and is the most important topic in the entire syllabus. In this chapter, you have to start with the basic concept of Charge as to what is meant by charge and how is charge induced. Though this will not be directly asked in GATE but in my view whichever terms you are using in daily life you should know their meaning as well.

Then you can start the study from the Coulomb’s Law and its vector form. This is one of the very basic laws to compute force between two point charges but then you must be very well aware as to how to solve it in terms of vectors. The direction of the force is very important.

Then you can start the concept of Electric Field Intensity and understand how to compute it for discrete as well as Continuous Charge Distributions such as Line Charge, Surface Charge, and Volume Charge. Here, we should focus on computing the field intensity for finite charge distributions in Gauss Law. Then you can move to the concept of Gauss law and understand the basics first of all such as the concept of Electric Flux and Electric Flux Density and the shape of Gaussian Surface. Then you have to understand how to apply Gauss law for an infinite line charge, surface charge, and volume charge density.

The next concept that we have to cover is the concept of Electric Potential in which you will understand the physical significance of Electric Potential and Electric Potential Energy. You have to understand how to compute Electric Potential Energy for Point Charge Distribution. Then you have to understand the concept of Electric Potential and Potential Energy of Continuous Charge Distributions such as line charge, surface charge, and volume charge. You also have to study the relationship between the electric field and electric potential. Then there is a small concept of Electric Dipole in which you have to understand how to determine Electric Field and Electric Potential.

Then we have to study one concept which is not included in Class 12th Physics which is Boundary Conditions in terms of Electric Field and Electric Flux Density. You have to study two interfaces Dielectric-Dielectric Interface and Dielectric-Conductor Interface. You also have to study one small concept regarding Continuity equation which will help you derive KCL and another one regarding Energy Density in which you have to determine Energy Density for constant or uniform electric field.

The last concept in this chapter includes the concept of Image Charge for the infinite conducting plane and semi-infinite plane and finding the Electric field in presence of Conducting Plane.

**Magnetostatics**

In this chapter, you have to study the sources of the magnetic field like the current element, surface current and volume current. The first law in this chapter Biot-Savart Law in which you have to find Magnetic Field Intensity due to line current and that too finite line current. The finite current distribution cannot be handled by Ampere’s Law. Then you have to study Ampere’s Law and the basics of Amperian Loop and the magnetic field due to infinite line current, sheet current and volume current. These laws form the basis of computation of Magnetic Field due to current distributions.

Then you have to understand the concept of Magnetic Flux Density and Magnetic Flux. You have to understand the concept of Permeability and the relation between Magnetic Field and Magnetic Flux Density. The next part of this chapter involves understanding the effect of Magnetic Field on a Moving Charge and a current carrying conductor. So, we compute the force due to Magnetic Field on a moving charge using Lorentz Force Law and force on a current carrying conductor. Then we study the concept of Magnetic Dipole realized using a current carrying loop and the torque on the magnetic dipole when it is kept in a uniform magnetic field.

Like Electrostatics here also we have to study about the Boundary Conditions when a magnetic field enters from one medium to the other. But the catch here is that in this chapter there is an extensive use of vectors and cross product so you need to be very well versed with these topics. If you can understand the Right-Hand Thumb Rule well then you can solve most of the problems of directions of Cross Product. Otherwise, you can use the component method to deal with such problems. In the last part of this chapter, you have to understand the concept of energy density in Magnetic Field.

**Maxwell’s Equations**

This is the last topic in GATE EE curriculum and this chapter opens with the concept of Electromagnetic Induction or Faraday’s Law and Lenz’s Law. In this topic, you have to understand the concept of Statically and Dynamically Induced EMF also called as Motional EMF. Then you will understand the modification made by Maxwell in Ampere’s Law and the concept of Displacement Current Density and Displacement Current. Then we summarize Maxwell’s Equations for Static and Dynamic Fields.

These are all the topics that you have to study in EMT for GATE EE exam curriculum and if you solve almost 5 problems on each of these topics then you will be in a good position to tackle the problems from this topic in GATE.

I hope you found this article helpful and now you will study EMT for GATE exam. Also, I hope I was able to clear your doubts regarding this subject. Please share it with your friends and other GATE aspirants so that they can also overcome the phobia of this subject.

Prepare for entire GATE (ECE) Syllabus by using – Koncept (2020), which is one of the best postal plans to prepare for GATE Exam

Similarly, you can know the strategy to prepare Electrical Machines and crack it with good score.