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Question

A string is stretched to a length of 1.2m and a standing wave is produced with a speed of 4m/s. The pattern for the standing wave is that of two anti-nodes between three nodes. What is the frequency that produces a standing wave?

 

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Answer 1

Stretched length of the string ,L = 1.2 m

Speed,v = 4 m/s

Standing wave is that of two anti-nodes between three nodes means  third harmonic.

Calculate the wave length by using the standing wave equation with  third harmonic.

λ = (2/3) L

   = (2/3) (1.2)

   = 0.8 m

Calculate the frequency .

f = v/λ

  = 4/0.8

  = 5 Hz

Therfore, the frequency is 5 Hz