The sound of an explosion on the surface of lake is heard by a boatman 100 m away and a diver 100 m below the point of explosion


#1

The sound of an explosion on the surface of lake is heard by a boatman 100 m away and a diver 100 m below the point of explosion.
(i) Of the two persons mentioned (boatman or diver); who would hear sound first ?
(ii) Give reason for your answer.
(iii) If the sound takes ‘t’ seconds to reach the boatman, approximately how much time it will take to reach diver ?


#2

(i) The diver hears the sound first.
(ii) It is because sound travels at 1450 m s^-1 in water and 330 m s^-1 in air.
(iii) The time in which sound reaches the diver is 330/1450 =0.227.