superposition

State 2 features of a stationary wave that distinguishes it from a progressive wave.

Energy is transferred along the direction of propagation of progressive waves while there is no propagation of energy in a stationary wave.

Amplitudes of vibrations of particles in a stationary wave vary from a minimum at the nodes to a maximum at the antinodes while the amplitude of a progressive wave remains the same.

Principle of Superposition

when two or more waves meet at a point, the resultant displacement at that point is equal to the vector sum of the displacements of the individual waves at that point.

Interference

Interference occurs when 2 or more waves superpose according to principle of superposition

Coherent

2 waves have constant phase difference and the same frequency

Conditions needed for observable interference to occur

The 2 waves must be coherent and they should be of similar or equal amplitude

Diffraction

Diffraction refers to the spreading of waves when they pass through a small opening or round an obstacle

(Note: Diffraction becomes more apparent as the slit opening decreases)

Why is it important to have a single slit in a Young's Double Slit experiment?

To produce coherent light sources at slits S1 and S2 (double slits)

How are stationary waves formed? (Typical)

A stationary wave is formed when 2 identical waves of the same amplitude, frequency and speed interfere. The 2 waves travel in opposite directions and overlap.