Q- The fundamental frequency of an open-open tube is 1500 Hz, when it is filled with helium at 0oC. What is the frequency when it is field with air at 0oC?
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Standing Waves: Vibrating string
Q- Figure shows the standing wave on a string, oscillating at frequency fo.
(a) How many antinodes will there be if the frequency is doubled to 2fo.
(b) If the tension in the string is increased by a factor of four, for what frequency will the string continue to oscillate as a standing wave with…
Sound: Resonance
Q- A 1.2 m long tube is closed at one end. A stretched wire is placed near the open end. The wire is 0.330 m long and has a mass of 9.60 g. It is fixed at both ends and oscillates in its fundamental mode. By resonance it sets the air column in the tube into oscillation at the column’s fundamental fr…
Sound: Doppler's Effect
Q- A commuter train passes a station platform at a constant speed of 40 m/s. The train horn sounded at its characteristic frequency of 320 Hz. What change in frequency is detected by a person standing on the platform as the train moves past from approaching to receding? (speed of sound in air is 340…
Standing Waves
Q- One of the 63.5 cm long strings of an ordinary guitar is tuned to produce the not B (frequency 245 Hz) when vibrating in its fundamental mode.
(a) find the speed of the transverse wave on this string.
(b) If the tension in the string is doubled, what will be the new fundamental frequency of the…
Sound: Intensity and Loudness
Q- A loudspeaker emits a power of 100 W and can be considered as appoint source. Find the sound intensity and sound level in dB at a distance of 10 m from the speaker. How close would you have to be to the speaker for the sound level to be at the threshold of pain (120 dB)? (The threshold of hearin…
Sound: Resonance
Q- A closed end organ pipe is sounded near a guitar causing one of the strings to vibrate with large amplitude. The string is 80% as long as the organ pipe. If both vibrate at their fundamental frequency, calculate the ratio of the speed of wave on the string to the speed of sound in air.
Sound: Intensity and Loudness
Q- When a pin of mass 0.120 g is dropped from a height of 0.80 m and 0.05% of its energy is converted into a sound pulse with a duration of 0.1 s.
(a) Estimate the range at which the dropped pin can be heard if the minimum audible intensity is 10-11 W/m2.
(b) Your result in (a) is much too larg…
Sound Waves: Wave-front
Q- A sound source is located somewhere along the x-axis. Experiments show that the same wave front simultaneously reaches listeners at x = -6 m and x = +8.0 m.
(a) What is the x co ordinate of the source?
(b) A third listener is positioned along the positive y-axis. What is her y coordinate if the…
Sound Waves: Interference
Q- Two in-phase loudspeakers are located at (x, y) coordinates (-2.5 m, +2.0 m) and (-2.5 m, -2.0 m). They emit identical sound waves with a 1.6 m wavelength and amplitude a. Determine the amplitude A of the sound at the five positions on the y-axis (x = 0) with the y values 0, 0.5 m, 1.0 m, 2.0 m.
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