An observer sitting in line of two tanks, watches the flashes of two tanks firing at each other at the same time, but he hears the sounds of two shots 2s and 3.5s after seeing the flashes. If distance between the two tanks is 510 m, find the speed of sound.

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

The audible frequency range of sound is :

1. 5 Hz - 10 kHz
2. 10 Hz - 20 kHz
3. 20 Hz - 20 kHz
4. 25 Hz - 40 kHz

A man can hear a sound of frequency :

1. 1 Hz
2. 1000 Hz
3. 200 Hz
4. 5 MHz