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A string 120cm in length sustains a standing wave with the points of the string at which the displacement amplitude is equal to 3.5 mm being seperated by 15cm. find,
a)the maximum displacement amplitude
b)to which overtone do these oscillations correspond?
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2 Answers
3points A ,B,C,D,E are having equal displacement
xE-xA=λ=4*15=60cm
as λ=2l/n=2 *120/n=60
n=4
so it corresponds to 4th harmonic
(distance of node from A =7.5CM as distance bet. B and C is 15 cm and node is between them .....)
taking node as origin and thus a=A sinkx
here a=3.5mm;k=2Π/λ and x=7.5cm
hence calculate A .................