Exam 17: Waves II

The speed of sound is 340 m/s. A plane flies horizontally at an altitude of 10,000 m and a speed of 400 m/s. When an observer on the ground hears the sonic boom the horizontal distance from the point on its path directly above the observer to the plane is (assume the speed of sound does not change with altitude):

During a time interval of exactly one period of vibration of a tuning fork, the emitted sound travels a distance:

Two small identical speakers are connected (in phase) to the same source. The speakers are 3 m apart and at ear level. An observer stands at X, 4 m in front of one speaker as shown. If the amplitudes are not changed, the sound he hears will be least intense if the wavelength is:

An organ pipe with one end closed and the other open has length L. Its fundamental frequency is proportional to:

An organ pipe with both ends open is 0.85 m long. Assuming that the speed of sound is 340 m/s, the frequency of the third harmonic of this pipe is:

The longitudinal displacement of a mass element in a medium as a sound wave passes through it is given by s = s_m cos (kx - ωt). Consider a sound wave of frequency 440 Hz and wavelength 0.75m. If s_m = 12 µm, how long does it take an element of air to move from a displacement of 12 µm to a displacement of 0 µm?

A tuning fork produces sound waves of wavelength $\lambda$ in air. This sound is used to cause resonance in an air column, closed at one end and open at the other. The length of this column CANNOT be:

Consider two imaginary spherical surfaces of different radius, both centered on a point sound source emitting spherical waves. The power transmitted across the larger sphere is ________ the power transmitted across the smaller and the intensity at a point on the larger sphere is ________ the intensity at a point on the smaller.

You are listening to an "A" note played on a violin string. Let the subscript "s" refer to the violin string and "a" refer to the air. Then:

A fire whistle emits a tone of 170 Hz. Take the speed of sound in air to be 340 m/s. The wavelength of this sound is about:

A plane produces a sonic boom only when:

If the speed of sound is 340 m/s, the shortest pipe, closed at one end, which resonates at 218 Hz is:

The sound intensity 5.0 m from point source is 0.50 W/m². The power output of the source is:

The largest number of beats per second will be heard from which pair of tuning forks?

The speed of sound in air is 340 m/s, and the density of air is 1.2 kg/m³. If the displacement amplitude of a 440-Hz sound wave is 10 µm, what is its pressure-variation amplitude?

A source emits sound with a frequency of 1000 Hz. Both it and an observer are moving in the same direction with the same speed, 100 m/s. If the speed of sound is 340 m/s, the observer hears sound with a frequency of:

If the speed of sound is 340 m/s, the two lowest frequencies of an 0.5 m organ pipe, closed at one end, are approximately:

If the sound level is increased by 10 db the intensity increases by a factor of:

In order for two sound waves to produce audible beats, it is essential that the two waves have:

Two stationary tuning forks (350 and 352 Hz) are struck simultaneously. The resulting sound is observed to: