Page No 162:
Question 1:
How does the sound produced by a vibrating object in a medium reach your ear?
Page No 163:
Question 3:
Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?
Page No 166:
Question 2:
How are the wavelength and frequency of a sound wave related to its speed?
Page No 166:
Question 4:
A 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 successive compressions from the source?
Page No 167:
Question 1:
In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature?
Page No 168:
Question 1:
An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s−1?
Page No 170:
Question 2:
What is the range of frequencies associated with
(a) Infrasound?
(b) Ultrasound?
Page No 172:
Question 1:
A submarine emits a sonar pulse, which returns from an underwater cliff in 1.02 s. If the speed of sound in salt water is 1531 m/s, how far away is the cliff?
Page No 174:
Question 5:
Which characteristics of the sound helps you to identify your friend by his voice while sitting with others in a dark room?
Page No 174:
Question 6:
Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why?
Page No 174:
Question 7:
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 m s−1.
Page No 174:
Question 9:
The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?
Page No 174:
Question 10:
Does sound follow the same laws of reflection as light does? Explain.
Page No 174:
Question 11:
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?
Page No 174:
Question 13:
A 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? Given, g = 10 m s−2 and speed of sound = 340 m s−1
Page No 174:
Question 14:
A sound wave travels at a speed of 339 m s−1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?
