# Physics Topic: Superposition

Explain the meaning of the term diffraction.

Show an understanding of experiments which demonstrate diffraction including the diffraction of water waves in a ripple tank with both a wide gap and a narrow gap.

Show an understanding of the terms interference and coherence.

Show an understanding of experiments which demonstrate two-source interference using water, light and microwaves.

Understand the conditions required if two-source interference fringes are to be observed.

Recall and solve problems using the equation

*x=D(wavelength)/a*for double-slit interference using light.(For H2 Syllabus only) Recall and solve problems by using the formula

*dsin(theta)=n x wavelength*and describe the use of a diffraction grating to determine the wavelength of light. [The structure and use of the spectrometer is not included.]