PHYS 105 1nd Edition Lecture 7 Outline of Last Lecture I. Waves and Superposition Outline of Current Lecture II.Sound WaveIII. Intensity and PowerIV. Reflection, Refraction and DiffractionCurrent LectureI. Sound Wave- Longitudinal pressure wave that travels in solid, liquid or gas - 3 important characteristics o Loudness = Related to amplitude o Pitch = Determined mainly by frequencyo Timbre = Related to frequency content of a sound wave - Speed of sound wave in idea gas ov =√yRTMoT =273+t [this is absolute temperature]oy∧R= 8.31Jmol × K [constants of gas]oM=molecular weight of gasII. Intensity and Power - Intensity = Power/Unit area- Power = Work/ Time - Peak Intensity of a sound is related to the peak sound pressure by I=p2pcop= peak pressure wave amplitude[p^2]op=density of a medium [pc]oc=speed of sound wave- Sound power is equal to the sound intensity times the area of the acoustic wave - Inverse Square Lawo Sound wave from a point source radiates outward uniformly over a sphereThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.oI=PowerArea=P4 π r2III. Reflection, Refraction and Diffraction - Reflection o Wave reflection from a curved barrier can be focused onto a pointo Wave reflected from a fixed end has 180° phase shift o Wave reflected from an open end does not have phase shift- Refractiono Waves travel through a different medium with a different wave speed will change the direction of travel - Temperature inversion o Temperature closer to ground is coldero Temperature higher up is warmero Speed of sound at high altitude from ground is faster than speed close to ground- Diffractiono When wave encounters obstructions, it can bend around the obstacle or pass through narrow
View Full Document
Unlocking...