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9th Class Science Sound Question Bank Sound Summative Objective Problems

  • question_answer
    A ship sends a signal and receives it back from the bottom of the sea after 6s. What is the depth of the sea at that place? (speed of sound in sea water is\[\text{145}0\text{ m}{{\text{s}}^{-\text{1}}}\])

    A)  4.35 km     

    B)  3.35 km

    C)  435 km                                

    D)  335 km

    Correct Answer: A

    Solution :

      Let the depth of the sea be ?d? Time interval before the echo is heard = 6s Speed of sound = 1450 m/s Distance travelled by sound =2d \[\therefore \] \[2d=speed\times time\] \[\Rightarrow \] \[2d=1450\times 6\] \[\Rightarrow \] \[d=4350\text{ }m\] \[\Rightarrow \] \[d=4.35\text{ }km\] \[\therefore \] The depth of the sea = 4.35 km                 


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