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Waves

Question
CBSEENPH11026311

Linear density of a string of is 1.3 x 10-4 kg/m and wave equation is y = 0.021 sin (x + 30t ), Find, the tension in the string where, x in metre and t in second

  • 0.12 N

  • 0.21 N

  • 1.2 N

  • 0.012 N

Solution

A.

0.12 N

Mass per unit length m = 1.3 × 10-4 kg/m

                               y = 0.021 sin (x + 30t)

Comparing with y = a sin ωt + 2π xλ

   a = 0.021,  ω = 30

    2πn = 30

⇒    n = 302π

We know that 

     2πλ = 1

∴     λ = 2π

Frequency,

       n = 1λTm

      302π = 12πT1.3 ×10-4

       T = 1.3 × 10-4 × 900

        T = 0.117 

        T = 0.12 N