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Waves

Question
CBSEENPH11026447

The equation of a progressive wave is given by y = 5 sin100 π t - 0.4 π x where y and x are in m and t is in s

(1) The amplitude of the wave is 5 m.

(2) The wavelength of the wave is 5 m.

(3) The frequency of the wave is 50 Hz.

(4) The velocity of the wave is 250 m s-1

Which of the following statements are correct?

  • (1), (2) and (3)

  • (2) and (3)

  • (1) and (4)

  • All are correct

Solution

D.

All are correct

 The equation of a given progressive wave is

         y = 5 sin  100 πt - 0.4 πx             ....(i)

The standard equation of a progressive wave is

        y = a sin ( ωt - kx )

Comparing equation (i) and (ii)

     α = 5 m

     ω = 100 π rad s-1

      k = 0.4 π m-1

(1) Amplitude of the wave, a = 5 m

(2) Wavelength of the wave,

         λ = 2πk

            = 2 π0.4 π

         λ = 50 m

(3) Frequency of he wave

        v= ω2 π

          = 100π2 π

      v = 50 Hz

(4) Velocity of the wave

       v = λ

           = ( 50 s-1 ) (5 m)

       v = 250 ms-1