ABSTRACT
The wave equations for both the electric and magnetic fields are second-order linear differential equations consisting of two differential terms, one spatial and the other temporal. A clear understanding of interference may start with addressing the superposition of waves that have the same plane of vibration and direction of propagation. In such a choice, the complexity of involving the vector nature of light can be minimized, because the electric fields of these waves are treated as scalars. This chapter will discuss ways by which one can determine the resultant of two or more waves. Among these are two simple but informative methods: one analytic, employing harmonic waves and adding them algebraically, and the other called the phasor diagram method. This method is most helpful when the superimposed waves have the same frequency.
