Flash and Thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. Why?

Which Characteristic of the sound helps you to identify your friend by his voice while sitting with others in a dark room?

Why is sound wave called a longitudinal wave?

Describe with the help of a diagram, how compressions and rarefactions are produced in air near a source of sound.

What is sound and how is it produced?

What is the range of frequencies associated with (a) Infrasound? (b) Ultrasound?