A steel tube of length 1.00 m is struck at one end. A person with his ear close to the other end hears the sound of the blow twice, one travelling through the body of the tube and the other through the air in the tube. Find the time gap between the two hearings. Use the table in the text for speeds of sounds in various substances. .
Given:
Velocity of sound in air
= 330 m/s
Velocity of sound through the steel tube 
= 5200 m/s
Here, Length of the steel tube S = 1 m
As we know,
=
and 
Where, 
is the time taken by the sound in air.
is the time taken by the sound in steel tube.
Therefore,
Required time gap 
Hence, the time gap between two hearings is 2.75 ms
1