Sound

The walls of the hall, built for music concerts should :

Which of the following is a cause of echo?

To hear a clear echo, the minimum distance between the reflecting surface and the observer should be :

How much should minimum distance between the source of sound and reflecting surface, so that an echo can be heard clearly?

A sound wave has frequency of 4 kHz and its wavelength is 35 cm, then how much time will it take to travel a distance of 3 km?

One important characteristic of sound is 'Pitch', which depends upon :

Shrillness of sound is determined by :

Two astronauts cannot hear each other on the Moon's surface, because :

Consider the following statements: 1. A flute of smaller length produces waves of lower frequency. 2. Sound travels in rocks in the form of longitudinal elastic waves only. Which of the statements given above is/are correct?

Consider the following statements: 1. In a seismograph, P waves are recorded earlier than S waves. 2. In P waves, the individual particles vibrate to and fro in the direction of wave propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation. Which of the statements given above is/are correct?