Bouncing Bending and Squeezing Waves Wave Phenomenon Huygens

Bouncing, Bending, and Squeezing Waves Wave Phenomenon

Huygen’s Principle • A wave front is made up of WAVELETS • Each WAVELET is a POINT SOURCE of circular waves • WAVE RAYS are lines PERPENDICULAR to wave fronts that show wave travel DIRECTION

Huygen’s Principle • Barrier blocks part of a WAVE FRONT • Remaining WAVELETS make a shorter WAVE • WAVE RAYS are BENT around CORNERS

Diffraction Opening much larger than WAVELENGTH of the wave Large number of WAVELETS in slit – LITTLE diffraction Opening is the same order as WAVELENGTH of the wave Small number of WAVELETS in slit – LOTS OF diffraction

Regular Reflection Normal – a perpendicular to a surface θi Incident ray Law of Reflection θr Reflected ray θi = θr

Diffuse Reflection from an irregular surface

Refraction • As a wave enters a new medium it MAY change speed. If it there is a change an the wave arrives at an angle its path will be BENT • Going into a SLOWER medium bends TOWARD the normal and wavelengths SHORTEN • Going into a FASTER medium bends AWAY from the normal and wavelengths LENGTHEN Which is the faster medium? Medium 1 – the wavelengths are longer and the ray is bent toward the normal going into medium 2

Polarization A polarizing filter blocks out all waves except those with particles moving in a certain direction. This only works for TRANSVERSE waves – LONGITUDINAL waves can NOT be polarized. Randomly polarized set of waves Polarizer Vertically polarized waves