Question

Give scientific reasons.

(a) In earlier times, people used to listen for the arrival of a distant train by putting their ear to the rail.

(b) The sounds generated by a tabla and a sitar are different.

(c) If you were both on the moon , your friend will not be able to hear you call.

(d) We can hear the movement of a mosquito's wings but we cannot hear the movement of our hands.

Answer 1

(a) In earlier times, people used to listen for the arrival of a distant train by putting their ear to the rail because they knew that sound travels faster through solids than gases. Thus, by putting their ear to the rails used to give them the idea of the arrival time of a train in advance.

(b) Due to difference in the pitch and timbre, the sound produced by a tabla and a sitar are different.

(c) We know that sound cannot travel through vacuum. Since there is no atmosphere on the moon atmosphere, so we cannot hear sound on the Moon.

(d) The frequency of sound produced by the movement of mosquito's wings is in the audible range of humans whereas that produced by the movement of our hands falls in the inaudible range. Due to this reason, we can hear the movement of a mosquito's wings but cannot hear the movement of our hands.