# Superposition

#### Chapter 10 - Superposition

In the GCE A Levels, we need to be able to explain the principle of superposition. This video will explain what this is, and also introduce the term coherence. We will see that when coherent waves superpose with one another, we will get a unique effect known as interference.

When studying the interference of two coherent waves at a point, we have to determine the phase difference between the waves at that point. For the GCE A Levels, the three main factors to consider will be the inherent phase difference of the sources, the number of reflections taken by the waves, and also the path difference of the waves. This video will explain how to put these factors together.

In the GCE A Levels, we need to describe how a stationary wave is formed. This video will address this and also briefly explain some basic features of the resultant stationary wave.
There are several key differences between progressive waves and stationary waves. In the GCE A Levels, we will need to describe the differences in how they move, and transfer energy. In addition, we will have to talk about the differences in describing the wavelengths of these waves, and also the amplitudes and phases of the particles on these waves.
In the GCE A Levels, we have to understand how to form stationary waves on a stretched string system. This video will explain the boundary conditions required to do this, and the general formula to describe stationary wave formation on a stretched string.
In the GCE A Levels, we have to understand how to form stationary waves in an open pipe system. This video will explain the boundary conditions required to do this, and the general formula to describe stationary wave formation in an open pipe.
In the GCE A Levels, we have to understand how to form stationary waves in an closed pipe system. This video will explain the boundary conditions required to do this, and the general formula to describe stationary wave formation in an closed pipe.
Diffraction is an important concept in the GCE A Levels. This video will explain what diffraction is, how to represent it, and the conditions under which you can have observable diffraction.
In the GCE A Levels, we have to study single-slit diffraction quantitatively. This video will explain the single-slit diffraction pattern obtained and how to analyse it.
Rayleigh’s Criterion explores on whether any two identical sources can be resolved by an aperture or not. In the GCE A Levels, we must know how to compare Rayleigh’s critical angle to the actual angle subtended at the aperture, and check if the sources are resolvable by the aperture.
The GCE A Levels requires us to study a two-source interference pattern, which is obtained when two coherent sources are placed some distance away from a screen. This video will explain the formation of this interference pattern, and also describe a simple formula to study it.
Diffraction gratings are a large number of closely-spaced slits, and when a wave is diffracted through it, a diffraction grating pattern is formed. The GCE A Levels requires us to analyse such patterns and this video will describe how this is done.