There's the potential energy due to the force on the nail. This potential energy was created when the magnet was made and you change it when you move the magnet near the nail. When the nail sticks to the magnet, going against the force of gravity, the magnetic potential energy is converted into gravitational potential energy.

 

According to my mind, the above discussion also suggests that once the magnet is created its energy becomes perpetual.I am not a perfect physics guy but according to my knowledge perpetual motions and fields(like magnetic field) do not obey the laws of physics.Am i right?

 

Although complex, understanding the fundamentals of Maxwell's Equations are not all that bad if you do some background work on the underlying mathematics (easy for me to say I hear you say!). For Faraday's and Ampere's Laws you need a grasp of how the Curl works and understand the interrelation of the electric and magnetic fields, namely a time-varying electric-field gives rise to a time-varying magnetic-field and how a time-varying magnetic-field gives rise to a time-varying electric-field. You should also be clear on the concepts of permittivity and permeability and there influence in the resulting EM waves.

Couple Faraday's and Ampere's Law (using substitution) and you have the wave equations for the plane wave solutions to the electric and magnetic fields. With the boundary conditions you now have all the fundamental tools for describing the complete interaction of EM waves within an environment.

Gauss's Laws are based around the divergence operator.

Maxwell's Equations become considerably more complicated when we start looking at practically applying them; thats where you need to concentrate in your EM Physics courses

Dave

Dave, you're absolutely correct! The equations are simple, the math behind it is what makes it difficult. I have learned all of the fundamentals of vector calculus from a prior course, but I have to reteach myself again since I don't use it ever!

I like this forum and will hopefully be using it next september, when I take the course again. I guarantee there will be a lot of very difficult questions, since our professor is a physics genius and it is all simple to him. He graduated University of Toronto at the age of 19 with a PhD in physics.. .

Steve