# Interference Pt II

 Pressure node = _______ antinode and vice versa 2 cases regarding the two ends of the air columns:  (State the cases) In case 2, where one end is open and the other closed (a type of displacement function), where is the displacement node vs displacement antinode? displacement antinode Case 1: Both ends open, e.g. fluteCase 2: one end opened and one end close, e.g. pipe organDisplacement Node at closed endDisplacement Antinode at open end In Case 1 (both ends open), both ends are ________ ________. State the formula for the natural frequencies, fn and that of λn and what harmonics are to be expected displacement antinodes  In Case 2: Pipe open at one end The closed end is a ________ _______. The open end is a _______ _______. State the formula for fn and λn and state the n series displacement nodedisplacement antinode  Depict the first, second and third resonance of the following  Musicians called f2,f3,...fn overtones f2 = ______ harmonic = ______ overtone f3 = ______ harmonic = ______ overtone  D. All the above  a) f = v/λ1 = v/2Lb) f = v/λ1 = v/2Lc) f = v/λ1 = v/4L∴ a=b>c Lowest frequency is the fundamental frequency f1 = v/2LA is wrong, if we use a thicker string, μ increases and v = (√T/μ) decreases, so f1 decreases**B** is right, increasing tension increases v which is directly proportional to f1C is wrong, plucking the string harder only increases AmplitudeD is wrong increasing L would decrease fundamental freq. (v/2L) To simplify the mathematical expressions, we take x = 0, Φ10 = Φ20 = π State the formulas for: D1 D2 D (be sure to specify which portion is the lower frequency and which is the higher frequency) Temporal interference occurs when the interfering waves have ______ ______ frequencies.  Define Beating and Beat frequency (state the formula and explain) The human ear can detect a beat frequency up to about ____ beats/second slightly different frequencies Beating: the periodic variation in amplitude at a given point due to the supersposition of two waves having slightly different frequenciesBeat frequency: the number of amplitude maxima one hears per second, it is the difference between the frequencies of the two sources fbeat = |f1 - f2|20 beats/second Restate the beat frequency formula and state the formula for amplitude modulation here (purple arrow): fb = |f1 - f2|The amplitude is slowly modulated as 2acos2πfbt At the 1st point, the waves are in _____. There is _______ interference. At the 2nd point, the waves are ____ ____ _____. There is _______ interference. At the 3rd point, the waves are _____ _____ _____. There is _______ interference. What would this look like if we had a superposition of the two sound waves phaseconstructive interferenceout of phasedestructive interference back in phaseconstructive interference This medium oscillates _____ at frequency fosc. The amplitude is ______ ______ at frequency fbeat. rapidly slowly modulated  fb = |f1-f2|fb = |340 - 341|fb =  1Hz or 1s-1T = 1/fb = 1/1s-1 = 1s Authorchikeokjr ID345640 Card SetInterference Pt II DescriptionInterference Pt II Updated2019-03-12T16:20:34Z Show Answers