Sound

Question 2Describe, with the help of a diagram, how compressions and rarefactions are produced in the air near a source of the sound.

Question 5Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. Why?

Question 6A 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...

Question 7Two children are at opposite ends of an aluminium rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the...

Question 8The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?

Question 9Does sound follow the same laws of reflection as light does? Explain.

Question 10When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of...

Question 11Give two practical applications of the reflection of sound waves.

Question 12A stone is dropped from the top of a tower 500 m high into a pond of water at the base of the tower. When is the splash heard at the top?...

Question 13A sound wave travels at a speed of 339 ms-1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?

Question 14What is reverberation? How can it be reduced?

Question 15What is loudness of sound? What factors does it depend on?

Question 16How is ultrasound used for cleaning?

Question 17Explain how defects in a metal block can be detected using ultrasound.

Question 3Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m/s in a given medium.

Question 4A person is listening to a tone of 500 Hz, sitting at a distance of 450 m from the source of the sound. What is the time interval between...

Question 1An echo is heard in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 ms-1?