The splash is heard 2.05S after the stone is dropped into a well of depth 19.6m The velocity of sound is g=9.8m/s2

Given that depth of well  h=19.6mTotal time taken for both sound and stone is given that  t=2.05S Time taken by the stone to reach the water of well t1=2hg=2×19.89.8=2×2=2S∴Time taken by sound t2=t−t1                                      =2.05−2=0.05S∴Velocity of sound =ht2                              =19.60.05=392m/s