Jatinder Singh Solutions for Chapter: Sound, Exercise 1: Expected Questions

A man standing in a gorge between two large cliffs gives a short sharp shout. He hears two echoes, the first after $1$ second and the next after $1.5$ seconds (after his shout). The speed of sound is $340 \mathrm{m} {\mathrm{s}}^{-1}$, calculate the distance of the man from each cliff and the distance between the cliffs.

Radio waves of speed $3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$ are reflected off the moon and received back on the earth, the time elapsed between the sending of the sign and receiving it back on the earth's surface is $2.5$ seconds. What is the distance of the moon from earth?

The wavelength of waves produced on the surface of water is $20 \mathrm{cm}$. If the wave velocity is $24 \mathrm{m} {\mathrm{s}}^{-1}$, calculate (i) the number of waves produced in one second and (ii) the time required is produce one wave.

A radar is able to detect the reflected waves from an enemy aeroplane, after a time interval of $0.02$ milliseconds. If the velocity of waves is $3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$, calculate the distance of the plane from the radar.

A man standing in front of a vertical cliff fires a gun. He hears the echo after $3$ seconds. On moving closer to the cliff by $82.5 \mathrm{m}$, he fires again. This time, he hears the echo after $2.5$ seconds. Calculate the distance of the cliff from the initial position of the man.

A man standing in front of a vertical cliff fires a gun. He hears echo after $3 \mathrm{s}$. On moving closer to the cliff by $82.5 \mathrm{m}$, he fires again. This time he hears the echo after $2.5 \mathrm{s}$. Calculate the velocity of sound.

A sound wave has a frequency $512 \mathrm{Hz}$ and wavelength $65 \mathrm{cm}$. Calculate the speed of sound.

The time period of a certain vibrating body is $0.08 \mathrm{s}$. Does this body produce sound audible to the human ear?