Kirchhoff’s laws

Kirchhoff’s laws are used to solve complicated electric circuits. Along with Ohm’s law, they are the first line of attack to solve any given circuit. However, bear in mind that these laws are valid only in the lumped matter discipline,

Variational Principle

The variational Principle(or Hamilton’s Principle), as proposed by Hamilton is also known as the Law of Least Action. It is a fundamental principle of Mechanics and is more basic than Newton’s laws of motion. We have discussed D’Alembert’s Principle before

Quantum Electrodynamics: A quick review

Based on Introduction to Elementary Particles– by David Griffiths. You can also watch Fermilab’s excellent introduction to QED here: