Question

A sound wave has a frequency of 4 kHz and a wavelength
of 40 cm. The time taken by the sound wave to travel a
distance of 3.2 km is:

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Answer 1

the relation between frequency, wavelength and speed is given by

             νλ= c............where ν is frequency

                                             λ is wavelength

so we can calculate the speed as

        4*40/100= 160/100= 1.6m/s

also we know that

speed = distance / time

       so time = distance / speed

           T =  3.2*1000m/1.6m/s

              =  2000 sec is the answer