Waves: Sound and Light crest an- node

WAVES MOVE ENERGY, NOT MATTER!

travelling wave-energy moves in node standing wave-energy moves in plane trough plane of paper, wave moves le-right of paper but the waves are staonary (guitar string) node: point of zero amplitude (energy) Wave Characteriscs an-node: point of maximum amplitude (energy)

diffracon: wave “bends” around opening in refracon: wave bends when reflecon: wave bounces from surface a boundary entering a new medium. Speed and wavelength changes.

Waves add CONSTRUCTIVELY or DESTRUCTIVELY Light and sound waves have a constant speed unless the waves change media. sound: 343 m/s in air light: 3 x 108 m/s in vacuum (similar value in air) 1 f = T T is period in seconds 1 f is frequency in Hz T = f λ is wavelength in meters v = λ f v is speed in m/s destrucve both construcve SOUND longitudinal wave: wave moves Sound Characteriscs le-right and maer is displaced right-le-right. All objects have a NATURAL frequency of vibraon and they can be made to the amplitude pressure waves: dark lines are vibrate (produce sound) by an outside source. of the wave tells you compressed air. This is known as a FORCED VIBRATION. how LOUD the sound is; larger means louder RESONANCE occurs when a forced vibraon Sound waves are a type of MECHANICAL wave known as LONGITUDINAL waves matches the natural frequency of vibraon. Mechanical waves move through solids, liquids or gases. SOUND CANNOT TRAVEL IN A VACUUM. In longitudinal waves the maer displacement Is parallel to the direcon of wave moon TRANSVERSE mechanical waves displace maer perpendicular to the direcon of wave moon

LIGHT Light Characteriscs

It has an ELECTRIC field and a MAGNETIC field. It behaves like a parcle and a wave. Photons are the fundamental parcle of light. Somemes they behave like parcles, somemes like waves. The DOUBLE SLIT experiment established the wave like properes of light. The PHOTOELECTRIC EFFECT established the parcle like behavior of light (Einstein). This effect says light must behave as a parcle to knock electrons off of the surface of a metal. Young’s double slit experiment. Light wave through two slits adds construcvely and destrucvely beyond the slits. light waves are TRANSVERSE WAVES that can travel without a medium. This type of transverse wave is known as an ELECTROMAGNETIC wave. high frequency of photons mean higher elecon speed. high intensity of light means more electrons removed.