A stone is dropped into a lake from a tower 500 metre high. The sound of the splash will be heard by the man approximately after

Options

A. 21 s
B. 10 s
C. 11.5 s
D. 14 s

Answer

C

Explanation

Time of fall of stone `t_(1) = sqrt((2h)/(g)) = sqrt((2 xx 500)/(10)) = 10 s`
Time taken by sound of splash to rise to tower
`t_(2) = (x)/(v) = (500)/(340) ~~ 1.5 s`
`:.` Total time `= t_(1) + t_(2) = 10 + 1.5 = 11.5 s`