Give two practical applications of reflection of sound waves?

When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?

Does sound follow the same laws of reflection as light does? Explain.

The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?

Two children are at opposite ends of an aluminum rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in air and in aluminum to reach the second child.

A person has a hearing range from 20 Hz to 20 KHz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies? Take the speed of sound in air as 344 ms–1?