Answer:
C) 2.24 s
Explanation:
Speed of sound in air at 25 degree = 346 m /s
Speed of sound in sea water = 1533 m/s
Time taken by sound to reach dolphin
= 1000 / 1533 = 0.6523 s
Time taken by sound to reach boatman
1000/ 346
= 2.89 s
Difference
= 2.89 - .6523
= 2.24 s