Question

How long will sound take to travel in (a) an iron rail and (b) air, both $3.3km$ in length respectively? Take speed of sound in air to be $330m{s}^{-1}$ and in an iron to be $5280m{s}^{-1}$.

• A. (a) $0.625s$, (b) $10s$
• B. (a) $10s$, (b) $0.625s$
• C. (a) $0.625s$, (b) $0.625s$
• D. None of the above

Answer 1

The correct option is A (a) $0.625s$, (b) $10s$

$Timetaken=\frac{Distancetravelled}{Speedofsound}$
The time taken through the iron rail and air are calculated as follows.

(a) In iron rail:

$Timetaken=\frac{3300m}{5280m/s}$, given that the speed of sound in iron rail is 5280 m/s and the length is 3.3 km, that is, 3300 meters.

= 0.625 seconds.

(b) In air:

$Timetaken=\frac{3300m}{330m/s}$, given that the speed of sound in iron rail is 330 m/s and the distance is 3.3 km, that is, 3300 meters.

= 10 seconds.

Hence, the time taken for the sound to travel through the iron rail and air are 0.625 seconds and 10 seconds respectively.