## A bat is flitting about in a cave, navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is 40 kHz. During one fast swoop directly toward a flat wall surface, the bat is moving at 0.03 times the speed of sound in air. What frequency does the bat hear reflected off the wall?

A bat is flitting about in a cave, navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is 40 kHz. During one fast swoop directly toward a flat wall surface, the bat is moving at 0.03 times the Read More …

## Earthquakes generate sound waves inside the earth. Unlike a gas, the earth can experience both transverse (S) and longitudinal (P) sound waves. Typically the speed of S wave is about  4.0 km s-1 , and that of P wave is  8.0 km s-1 .A seismograph records P and S waves from an earthquake. The first P wave arrives 4 min before the first S wave. Assuming the waves travel in straight line, at what distance does the earthquake occur?

Earthquakes generate sound waves inside the earth. Unlike a gas, the earth can experience both transverse (S) and longitudinal (P) sound waves. Typically the speed of S wave is about  4.0 km s-1 , and that of P wave is  8.0 km Read More …

## A SONAR system fixed in a submarine operates at a frequency 40.0 kHz. An enemy submarine  moves towards the SONAR with a speed of  360 . kmh-1 What is the frequency of sound reflected by the submarine? Take the speed of sound in water to be  1450 m s-1 .

A SONAR system fixed in a submarine operates at a frequency 40.0 kHz. An enemy submarine  moves towards the SONAR with a speed of  360 . kmh-1 What is the frequency of sound reflected by the submarine? Take the speed of sound Read More …

## One end of a long string of linear mass density  8.0× 10-3 kgm-1 is connected to an electrically driven tuning fork of frequency 256 Hz. The other end passes over a pulley and is tied to a pan containing a mass of 90 kg. The pulley end absorbs all the incoming energy so that reflected wave s at this end have negligible amplitude. At t = 0, the left end (fork end) of the string x = 0 has zero transverse displacement (y = 0) and is moving along positive y-direction. The amplitude of the wave is 5.0 cm. Write down the transverse displacement y as function of x and t that describes the wave on the string.

One end of a long string of linear mass density  8.0× 10-3 kgm-1 is connected to an electrically driven tuning fork of frequency 256 Hz. The other end passes over a pulley and is tied to a pan containing a mass of 90 Read More …

## A narrow sound pulse (for ex ample, a short pip by a whistle) is sent across a medium. (a) Does the pulse have a definite (i) frequency, (ii) wavelength, (iii) speed of propagation? (b) If the pulse rate is 1 after every 20 s, (that is the whistle is blown for a split of second after every 20 s), is the frequency of the note produced by the whistle equal to  1 / 20  or 0.05 Hz?

A narrow sound pulse (for ex ample, a short pip by a whistle) is sent across a medium. (a) Does the pulse have a definite (i) frequency, (ii) wavelength, (iii) speed of propagation? (b) If the pulse rate is 1 after every Read More …

## A travelling harmonic wave on a string is described by

A travelling harmonic wave on a string is described by

## A train, standing in a station-yard, blows a whistle of frequency 400 Hz in still air. The wind starts blowing in the direction from the yard to the station with at a speed of  1 0 ms-1 . What are the frequency, wavelength, and speed of sound for an observer standing on the station’s platform? Is the situation exactly identical to the case when the air is still and the observer runs towards the yard at a speed of  10 m s-1 ? The speed of sound in still air can be taken as  340 m s-1 .

A train, standing in a station-yard, blows a whistle of frequency 400 Hz in still air. The wind starts blowing in the direction from the yard to the station with at a speed of  1 0 ms-1 . What are the frequency, Read More …

## A train, standing at the outer signal of a railway station blows a whistle of frequency 400 Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of  10 m s-1 , (b) recedes from the platform with a speed of  10 m s-1 ? (ii) What is the speed of sound in each case? The speed of sound in still air can be taken as  340 m s-1 .

A train, standing at the outer signal of a railway station blows a whistle of frequency 400 Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a Read More …

## Explain why (or how): In a sound wave, a displacement node is a pressure antinode and vice versa, Bats can ascertain distances, directions, nature, and sizes of the obstacles without any “eyes”, A violin note and sitar note m ay have the same frequency, yet we can distinguish between the two notes, Solids can support both longitudinal and transverse waves, but only longitudinal waves can propagate in gases, and the shape of a pulse gets distorted during propagation in a dispersive medium

Explain why (or how): In a sound wave, a displacement node is a pressure antinode and vice versa, Bats can ascertain distances, directions, nature, and sizes of the obstacles without any “eyes”, A violin note and sitar note m ay have Read More …

## Two sitar strings A and B playing the note ‘Ga’ are slightly out of tune and produce beats of frequency 6 Hz. The tension in the string A is slightly reduced and the beat frequency is found to reduce to 3 Hz. If the original frequency of A is 324 Hz, what is the frequency of B?

Two sitar strings A and B playing the note ‘Ga’ are slightly out of tune and produce beats of frequency 6 Hz. The tension in the string A is slightly reduced and the beat frequency is found to reduce to 3 Hz. Read More …

## A pipe 20 cm long is closed at one end. Which harmonic mode of the pipe is resonantly excited by a 430 Hz source? Will the same source be in resonance with the pipe if both ends are open? (Speed of sound in air is340 m s-1 ).

A pipe 20 cm long is closed at one end. Which harmonic mode of the pipe is resonantly excited by a 430 Hz source? Will the same source be in resonance with the pipe if both ends are open? (Speed of sound Read More …

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