Issues in calibration. Primary reference standards. A reference standard for a unit of measurement is an artifact that embodies the quantity of interest in a way that ties its value to the reference base. At the highest level, a primary reference standard is assigned a value by direct comparison with the reference base.
Refraction of Sound Waves. The speed of a wave depends on the elastic and inertia properties of the medium through which it travels. When a wave encounters different medium where the wave speed is different, the wave will change directions.
Diffraction Definition. Refraction is the bending of light or sound waves that moves from one medium to another and a change in speed is forced. Refraction creates optical phenomenon and illusions. Diffraction of Light is bending of the light waves around an object.efraction is the bending of light or sound waves that moves from one medium to another and a change in speed is forced. Refraction creates optical phenomenon and illusions. Diffraction of Light is bending of the light waves around an object.